Change copy around enabling/disabling following users

What does this MR do and why?

Copy around enabling/disabling following users was misleading, I fixed it. The checked checkbox means that following users is ENABLED.

Screenshots or screen recordings

Before:

AFTER:

How to set up and validate locally

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

1. Enable the Feature flag

   Feature.enable(:disabling_following)

2. Visit any user's profile. See if the follow button is present and click to follow.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

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