Sync only changed attributes on project and project namespace

What does this MR do and why?

Currently we are seeing some desyncronization between some attributes of the Project and its correspoinding Namespaces::ProjectNamespace association. see #358410 (closed)

We are currently keeping in sync 5 attributes: name, path, namespace, visibility_level, shared_runners_enabled, however in reality sometimes we do see some desyncronization.

Unfortunately it is not clear how the desynchronization happens given the attributes are updated in before_validation callback.

This MR tries to remove an extra check when attributes are updated and monitor if any new issues appear in the meantime.

#358410 (closed)

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