Revise migration pointer un-dismissal to work for all admins

[mukeshpanchal27]

Summary

Follow-up to #915 (comment)

Scenario that resolved by this PR:

If we implement suggested changes. The behaviour with the migration pointer is as follows:

• Upon plugin release, the migration pointer becomes visible on the site.
• When the non-technical team logs in, they see the migration pointer.
• If they dismiss the pointer, it won't appear for them again.
• However, the technical team, when logging in, never encounters this migration pointer.

That wouldn't be the case, maybe there was a misunderstanding or I didn't explain it well. The pointer wouldn't be dismissed for every user, it would only be "un-dismissed" for every user.

In other words:

• User A dismisses the pointer.
• User B still sees the pointer.
• User B performs the migration.
• Later, user B for some reason deactivates a standalone plugin and reactivates the corresponding module again.
• Now there's the difference:
  • Based on the current PR code, only user B would see the pointer again, but the problem applies to the entire site, so I think user A should see the pointer again as well.
  • In my proposal, both user B and user A would see the pointer again as a result of the change from user B, so user A would be aware of the problem and then could fix it (e.g. if user B goes on holidays).

Checklist

• PR has either [Focus] or Infrastructure label.
• PR has a [Type] label.
• PR has a milestone or the no milestone label.

[felixarntz]

@mukeshpanchal27 Mostly looks great! A few points of feedback, most importantly regarding the query approach.

[felixarntz]

@mukeshpanchal27 The approach looks good to me now, there are only a few last quirks to iron out.

[mukeshpanchal27]

@swissspidy @felixarntz PR is ready for review.

[felixarntz]

Thanks @mukeshpanchal27, looks great!

[felixarntz]

@swissspidy Could you give this another look when you get a chance?