Add unit tests for Connector Configured status when TLS secret is missing

[AryanP123]

Add test case(s) to TestSite_CheckConnector in internal/kube/site/site_test.go.
When a Connector references spec.tlsCredentials but the secret is not in the profiles cache, CheckConnector should set Configured=False with a message like TLS credentials secret "my-tls" not found.

[AryanP123]

Can be worked on once #2449 is merged