🐛(dimail) fix broken auth while resetting passwords

Dimail client's "reset password" method was using basic auth while
dimail expects a token for this endpoint. Fixed it.

src/backend/mailbox_manager/tests/api/mailboxes/test_api_mailboxes_reset_password.py

@@ -124,6 +124,12 @@ def test_api_mailboxes__reset_password_admin_successful(role):
     client.force_login(access.user)
     dimail_url = settings.MAIL_PROVISIONING_API_URL
 
+    responses.add(
+        responses.GET,
+        f"{dimail_url}/token/",
+        body=dimail.TOKEN_OK,
+        status=200,
+    )
     responses.add(
         responses.POST,
         f"{dimail_url}/domains/{mail_domain.name}/mailboxes/{mailbox.local_part}/reset_password/",
@@ -169,6 +175,12 @@ def test_api_mailboxes__reset_password_connexion_failed():
     client.force_login(access.user)
 
     dimail_url = settings.MAIL_PROVISIONING_API_URL
+    responses.add(
+        responses.GET,
+        f"{dimail_url}/token/",
+        body=dimail.TOKEN_OK,
+        status=200,
+    )
     responses.add(
         responses.POST,
         f"{dimail_url}/domains/{mail_domain.name}/mailboxes/{mailbox.local_part}/reset_password/",