Credentials: Updating fetch logic & moving from soft delete

[AkhileshNegi]

Is your feature request related to a problem? Please describe.
There are two issues with how credentials are handled right now:

Deleting a credential just marks it inactive, but doesn’t update deleted_at. We don’t really need soft deletes here, so instead of juggling two flags, we should hard delete credentials and drop the deleted_at column.

When fetching, the query only checks for is_active = true. That means if a credential exists but is inactive, the system thinks nothing exists. Then when trying to create a new credential, it throws an error saying the credential already exists for that org/project combo.

Describe the solution you'd like

Stop soft deleting → just hard delete credentials and remove the deleted_at column.

Don’t filter by is_active = true when fetching → fetch all credentials, so the system doesn’t trip over its own state.