fix: Cleanup and fix Authenticatable concern exposed helpers

[dimkl]

Breaking changes:

• Rename clerk_verified_session_claims to clerk_session_claims
• Drop clerk_verified_session_token
• Drop clerk_session
• Drop clerk_reverify_session! - not implemented

Changes:

• Drop unused fetch of session resource in ProxyV2

[dimkl]

Comments applied and description updated! Could you take another look? @gkats , @georgepsarakis , @agis