Improve UI text of group settings Permissions and group features section

What does this MR do and why?

Improves UI text of the Permissions section in the group settings page.

Part of #350107 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. On the top bar, select Menu > Projects and find your project.
2. On the left sidebar, select Settings > General.
3. Expand Permissions and group features.

View the UI text of this section.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.