Follow-up: Update shared/access_tokens views to use the `AccessTokens` translation namespace

The following discussion from !66915 (merged) should be addressed:

• @jiaan started a discussion: (+1 comment)

  Nitpick (non-blocking): WDYT about namespacing these new strings with AccessTokens?

As per our minimizing translation changes guidelines, I think it makes sense that everything in this area uses the AccessTokens namespace. Currently, nothing does. But, it would add good context for translators.

Implementation plan

1. Update all views in shared/access_tokens to use the AccessTokens namespace with translated strings
2. Update locale/gitlab.pot