✅(backend) mock identities' name when searching a user

When testing user search, we generated few identities
with mocked emails.

Name attribute was introduced on Identity model. Currently
names are freely and randomly generated by the factory.

To make this mocked data more realist, mock also identities'
names to match their email.

It should not break existing tests, and will make them more
predictable when introducing advanced search features.

src/backend/core/tests/test_api_users.py

@@ -54,15 +54,15 @@ def test_api_users_authenticated_list_by_email():
     partial query on the email.
     """
     user = factories.UserFactory(email="tester@ministry.fr")
-    factories.IdentityFactory(user=user, email=user.email)
+    factories.IdentityFactory(user=user, email=user.email, name="john doe")
 
     client = APIClient()
     client.force_login(user)
 
-    dave = factories.IdentityFactory(email="david.bowman@work.com", is_main=True)
-    nicole = factories.IdentityFactory(email="nicole_foole@work.com", is_main=True)
-    frank = factories.IdentityFactory(email="frank_poole@work.com", is_main=True)
-    factories.IdentityFactory(email="heywood_floyd@work.com", is_main=True)
+    dave = factories.IdentityFactory(email="david.bowman@work.com", name="david bowman", is_main=True)
+    nicole = factories.IdentityFactory(email="nicole_foole@work.com", name="nicole foole", is_main=True)
+    frank = factories.IdentityFactory(email="frank_poole@work.com", name="frank poole", is_main=True)
+    factories.IdentityFactory(email="heywood_floyd@work.com", name="heywood floyd", is_main=True)
 
     # Full query should work
     response = client.get(
@@ -119,14 +119,16 @@ def test_api_users_authenticated_list_multiple_identities_single_user():
     User with multiple identities should appear only once in results.
     """
     user = factories.UserFactory(email="tester@ministry.fr")
-    factories.IdentityFactory(user=user, email=user.email)
+    factories.IdentityFactory(user=user, email=user.email, name="eva karl")
 
     client = APIClient()
     client.force_login(user)
 
     dave = factories.UserFactory()
-    factories.IdentityFactory(user=dave, email="david.bowman@work.com")
-    factories.IdentityFactory(user=dave, email="david.bowman@fun.fr")
+    factories.IdentityFactory(
+        user=dave, email="dave.bowman@work.com", name="dave bowman"
+    )
+    factories.IdentityFactory(user=dave, email="dave.bowman@fun.fr", name="dave bowman")
 
     # Full query should work
     response = client.get(
@@ -145,21 +147,23 @@ def test_api_users_authenticated_list_multiple_identities_multiple_users():
     on their best matching identity.
     """
     user = factories.UserFactory(email="tester@ministry.fr")
-    factories.IdentityFactory(user=user, email=user.email)
+    factories.IdentityFactory(user=user, email=user.email, name="john doe")
 
     client = APIClient()
     client.force_login(user)
 
     dave = factories.UserFactory()
     dave_identity = factories.IdentityFactory(
-        user=dave, email="david.bowman@work.com", is_main=True
+        user=dave, email="dave.bowman@work.com", is_main=True, name="dave bowman"
     )
-    factories.IdentityFactory(user=dave, email="babibou@ehehe.com")
+    factories.IdentityFactory(user=dave, email="babibou@ehehe.com", name="babihou")
     davina_identity = factories.IdentityFactory(
-        user=factories.UserFactory(), email="davina.bowan@work.com"
+        user=factories.UserFactory(), email="davina.bowan@work.com", name="davina"
     )
     prue_identity = factories.IdentityFactory(
-        user=factories.UserFactory(), email="prudence.crandall@work.com"
+        user=factories.UserFactory(),
+        email="prudence.crandall@work.com",
+        name="prudence",
     )
 
     # Full query should work
@@ -203,12 +207,14 @@ def test_api_users_authenticated_list_multiple_identities_multiple_users():
 def test_api_users_authenticated_list_uppercase_content():
     """Upper case content should be found by lower case query."""
     user = factories.UserFactory(email="tester@ministry.fr")
-    factories.IdentityFactory(user=user, email=user.email)
+    factories.IdentityFactory(user=user, email=user.email, name="eva karl")
 
     client = APIClient()
     client.force_login(user)
 
-    dave = factories.IdentityFactory(email="DAVID.BOWMAN@INTENSEWORK.COM")
+    dave = factories.IdentityFactory(
+        email="DAVID.BOWMAN@INTENSEWORK.COM", name="DAVID BOWMAN"
+    )
 
     # Unaccented full address
     response = client.get(
@@ -232,12 +238,12 @@ def test_api_users_authenticated_list_uppercase_content():
 def test_api_users_list_authenticated_capital_query():
     """Upper case query should find lower case content."""
     user = factories.UserFactory(email="tester@ministry.fr")
-    factories.IdentityFactory(user=user, email=user.email)
+    factories.IdentityFactory(user=user, email=user.email, name="eva karl")
 
     client = APIClient()
     client.force_login(user)
 
-    dave = factories.IdentityFactory(email="david.bowman@work.com")
+    dave = factories.IdentityFactory(email="david.bowman@work.com", name="david bowman")
 
     # Full uppercase query
     response = client.get(
@@ -261,12 +267,14 @@ def test_api_users_list_authenticated_capital_query():
 def test_api_contacts_list_authenticated_accented_query():
     """Accented content should be found by unaccented query."""
     user = factories.UserFactory(email="tester@ministry.fr")
-    factories.IdentityFactory(user=user, email=user.email)
+    factories.IdentityFactory(user=user, email=user.email, name="john doe")
 
     client = APIClient()
     client.force_login(user)
 
-    helene = factories.IdentityFactory(email="helene.bowman@work.com")
+    helene = factories.IdentityFactory(
+        email="helene.bowman@work.com", name="helene bowman"
+    )
 
     # Accented full query
     response = client.get(