Make secretNamespace optional

[p4block]

Feature description

Make any kind of namespace field in secrets.infisical.com/v? optional

Why would it be useful?

If not stated, both the authentication.secretAuth.credentialsRef.secretNamespace and managedSecretReference.secretNamespace should inherit the namespace of the InfisicalSecret itself

Additional context

As an ArgoCD user, specially after the recent change that requires the token secret to exist in the same namespace as the InfisicalSecret, these values seem to be boilerplate.
I'm not knowledgeable of the specifics and may be missing something, but I think

• The token secretNamespace no longer serves a purpose after cross-namespace secretrefs were nerfed.
• The managed secretNamespace with Argo can just be guessed to be == to the Infisical secret namespace for most users.