♻️(backend) rely on set_role_to from DocumentAskForAccess abilities

Like in other abilities, we compute a set_role_to property on the
abilities. This set_role_to contains all the roles lower or equal than
the current user role. We rely on this propoerty to validate the accept
endpoint and it will be used by the front allpication to built the role
select list.

src/backend/core/tests/documents/test_api_documents_ask_for_access.py

@@ -287,6 +287,7 @@ def test_api_documents_ask_for_access_list_authenticated_own_request():
                     "update": False,
                     "partial_update": False,
                     "retrieve": False,
+                    "set_role_to": [],
                 },
             }
         ],
@@ -356,6 +357,15 @@ def test_api_documents_ask_for_access_list_owner_or_admin(role):
 
     response = client.get(f"/api/v1.0/documents/{document.id}/ask-for-access/")
     assert response.status_code == 200
+
+    expected_set_role_to = [
+        RoleChoices.READER,
+        RoleChoices.EDITOR,
+        RoleChoices.ADMIN,
+    ]
+    if role == RoleChoices.OWNER:
+        expected_set_role_to.append(RoleChoices.OWNER)
+
     assert response.json() == {
         "count": 3,
         "next": None,
@@ -375,6 +385,7 @@ def test_api_documents_ask_for_access_list_owner_or_admin(role):
                     "update": True,
                     "partial_update": True,
                     "retrieve": True,
+                    "set_role_to": expected_set_role_to,
                 },
             }
             for document_ask_for_access in document_ask_for_accesses
@@ -467,6 +478,13 @@ def test_api_documents_ask_for_access_retrieve_owner_or_admin(role):
         f"/api/v1.0/documents/{document.id}/ask-for-access/{document_ask_for_access.id}/"
     )
     assert response.status_code == 200
+    expected_set_role_to = [
+        RoleChoices.READER,
+        RoleChoices.EDITOR,
+        RoleChoices.ADMIN,
+    ]
+    if role == RoleChoices.OWNER:
+        expected_set_role_to.append(RoleChoices.OWNER)
     assert response.json() == {
         "id": str(document_ask_for_access.id),
         "document": str(document.id),
@@ -481,6 +499,7 @@ def test_api_documents_ask_for_access_retrieve_owner_or_admin(role):
             "update": True,
             "partial_update": True,
             "retrieve": True,
+            "set_role_to": expected_set_role_to,
         },
     }