Fix signup warning (#12213)

- Should only fire on an actual signup attempt

src/backend/InvenTree/InvenTree/auth_overrides.py

@@ -114,6 +114,9 @@ class RegistrationMixin:
         """
         if registration_enabled(self.REGISTRATION_SETTING):
             return True
+        # Only warn when this is an actual signup submission, not when called as
+        # a feature-availability check during login or other auth flows.
+        if request and request.method == 'POST' and 'signup' in request.path:
             logger.warning(
                 f'INVE-W12: Signup attempt blocked, because registration is disabled via setting {self.REGISTRATION_SETTING}.'
             )