* Running the tests only in the ember cli env hid the fact that the pending posts feature wasn't working in the legacy environment
* Tests were using ember-cli-only APIs while there are widely used testing APIs in Discourse that support both ember envs
* `ember-test-selectors` was in both dependencies and devDependencies in discourse/package.json
* `qunit-dom` in package.json was not only unused but also defunct, as it wasn't pulled into the legacy env app
A followup to #14501, and #15128.
Currently when a user creates posts that are moderated (for whatever
reason), a popup is displayed saying the post needs approval and the
total number of the user’s pending posts. But then this piece of
information is kind of lost and there is nowhere for the user to know
what are their pending posts or how many there are.
This patch solves this issue by adding a new “Pending” section to the
user’s activity page when there are some pending posts to display. When
there are none, then the “Pending” section isn’t displayed at all.
