Fixes #19878

[ci skip]

add modal my gawd

To ensure that we don't accidentally use any of the aliases.
This should prevent any future regressions from #12761.
Also updates the test suite since it now can't use these aliases either.

[Fixes #15953] Implement `assert.expect` in each unit test

Fixes #15136.
Closes #15345.
Closes #15314.
Refs #14724, #14927.

Refs #15893

Add tests for `aria-hidden` of modal

Use strictEqual of 1 here instead of 2 asserts

[skip validator]

[skip validator]

* register the callback before invoking the toggling
* listen for `hidden` instead of `hide`
* account for the possibility of the associated `show` event being preventDefault-ed

Adds relevant unit tests.

#11464 - Fix JS noConflict mode - Refactor all plugins to use an internal reference to the jQuery plugin, because in noConflict mode you can never expect to be defined on the jQuery object