Draft: Rename "Watch" notification level to "All"

What does this MR do and why?

Renames the "Watch" notification level to "All".

MR acceptance checklist

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How to set up and validate locally

• http://gdk.test:3000/-/profile/notifications
• http://gdk.test:3000/Commit451 (any group)
• http://gdk.test:3000/Commit451/lab-coat (any project)