EnsureNamespaceExistsAndIsReady

Problem: During restore for every resource within the namespace, we are calling the check to await on if namespace exists (wait for 10 min polling). For instance, if we have 100 resources in a namespace that itself is in terminating state for very long then it impacts the restore flow to get stuck/halt and it too increases the time to restore as it does it for each resource in the same namespace.

Originally posted by @mayankagg9722 in #7516 (comment)