* Unskip EQL tests

These _should_ be fixed with the latest ES on master, but let's see if
CI disagrees.

* Wait until alerts have populated on Rule Details

Occasionally our tests hit a scenario where the rule has executed (its
status is "succeeded"), but the generated alerts have not populated in
the same time frame. In this case the test fails oddly, saying that the
"alert count" element is not there when it is.

I attempted to improve the error message by using a .should() with a
callback, but that lead to even stranger behavior as the .should() would
fail once (expected), and then not be able to find the element a second
time. :(

So we instead focus on fixing the real problem, here: wait until alerts
populate (have a non-zero count) before performing the assertion.
Because the page will not update automatically, we can't rely on
cypress' retryability and must instead assert, click Refresh, and assert
again, much like we're doing while waiting for the rule to execute. And
like `waitForTheRuleToBeExecuted`, we're using a while loop that has no
guarantee of ever exiting :(

* More robust cypress assertions

* Uses should with a text matcher instead of using invoke('text')
* Use of not.equal between a string and an element may have been a false
  positive

* Perform cypress loops in a manner guaranteed to exit

We have a few tasks that require polling for some background work to be
completed. The basic form is: assert the byproduct, or refresh the page
and try again.

We were previously doing this with a while loop, which was not
guaranteed to ever complete, leading to cryptic failures if the process
ever hung.

Instead, this implements a safer polling mechanism with a definite
termination similar to the cypress-wait-until plugin.

* Update other specs that are asserting on alerts

* Do not automatically refresh the page
  * This is only necessary if we're not in the state we need. The
    `waitFor` helper functions automatically reload whatever needs to be
    reloaded, so we're delegating this task to them.
* Ensure we wait for alerts to be nonzero before our assertion
  * Otherwise we get some strange behavior around this field's
    availability; see previous commits

* Remove unused import

* Fix false positive in Rule Creation specs

Threat Match Rules introduced an additional query input, causing our
CUSTOM_QUERY_INPUT to be ambiguous.

However, instead of failing due to the ambiguity, the behavior of
cypress seems to be to pass! While I haven't yet tracked down the cause
of these false positives, disambiguating these selectors is the
immediate fix.

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>
# Conflicts:
#	x-pack/plugins/security_solution/cypress/integration/alerts_detection_rules_eql.spec.ts
(cherry picked from commit 3fc1f8c)