Hide "Queue" action if PR is not approved

## Describe the bug

This sadly isn't the first time that I've sat on a tab trying to queue a PR thinking it was approved. It would be nice in the checks page if this was indicated and, if required, not even allow the queue button to be there.

## Steps to Reproduce

* go to the checks page for an unapproved PR
* click Queue and wait 5ish s
* click Queue again. wait
* Ctrl+shift+r
* click Queue. wait
* navigate to merge bot page. See nothing is queued
* ask in #merge-bot
* navigate to comments page and realize you're an idiot and that you spammed yourself with email

## Expected behavior

Either the Queue button wouldn't be available with something stating that it is not approved or clicking queue would indicate a message that it is not approved (preferably the former).

Start at the checks page and trace the Queue action for an unapproved pull request; the issue names no source file or test. Done means the Queue button is unavailable for unapproved PRs and the page clearly states that approval is required.

Written by the indexing model from the issue text.