Improving a flakey uninstall from allapps test.

Previously the test froze the all apps list before the uninstall action, but what we are testing here is that the all apps list does change. Also included is a small refactor to use the same wait method for this test and a second test.

Test: Ran Locally on Device
Bug: b/258071914
Change-Id: Ic18be39130fbd7b7e1214d6fc60c1afa30ddf078