Fix project access token creation group settings link

What does this MR do?

Follow up to !57756 (merged)

Since disabling/enabling project access token creation is only allowed for top-level groups, the text that prompts the user to enable token creation should link to the project's group's root ancestor's settings. Previously it would link to the project's group settings, and if that group was not a top-level group, then there'd be no option to enable/disable token creation, which is confusing for the user. The text+link also only render if the user can admin the top-level group (otherwise they'd be brought to a 404 page).

Screenshots (strongly suggested)

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