Remove geo_use_clone_on_first_sync feature flag

What does this MR do and why?

Remove geo_use_clone_on_first_sync feature flag

• Introduced by: !77143 (merged)
• Rollout: #357462 (closed)

Cleanup

From: https://docs.gitlab.com/ee/development/feature_flags/controls.html#cleanup-chatops

Run:

/chatops run feature delete geo_use_clone_on_first_sync --dev --pre --staging --staging-ref --production