Add wording about group access token max lifetime

What does this MR do and why?

Add wording to reflect that Group Access Tokens are also subject to the maximum allowable lifetime setting available in self managed Ultimate installations for personal access tokens. This is a follow on to !80675 (merged) except for Group access tokens.

Screenshots or screen recordings

How to set up and validate locally

1. In a self-managed installation, as administrator, create a Maximum allowable lifetime for personal access token and check enforce personal access token expiration under Settings->General.
2. In a group, attempt to create a group access token
3. The message that a limit is in place with an enforced expiration date will appear

MR acceptance checklist

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