UI: Do not expire direct memberships in subgroups and projects

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What does this MR do and why?

This MR adds a link to the UI that explains access expiration when inviting users or groups to projects or groups.

This is a follow-up to this backend change and is related to #471051

🛠 with ❤ at Siemens

MR acceptance checklist

MR Checklist ( @nwittstruck)

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the javascript style guides
• Conforms to the database guides

Screenshots or screen recordings

Before	After	Documentation Link
		/doc/user/project/members/index.md#add-users-to-a-project
		/doc/user/project/members/sharing_projects_groups#invite-a-group-to-a-project
		/doc/user/group/index.md#add-users-to-a-group
		/doc/user/project/members/sharing_projects_groups#invite-a-group-to-a-group

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Manage Project members
2. Manage Group members

Related to #471051