Attempting to fix flakes in AllAppsIconToHomeTest

Pressing an icon in AllApps doesn't show a context menu.

The flake doesn't repro locally, the suspects are:
1. Too short wait time
2. App being partially covered by navbar.

Hence the fixes.

This patch is temporary, and will be replaced with a permanent one when
this will be converted to TAPL.

Test: AllAppsIconToHomeTest
Change-Id: I0a03ff8827a5bc7940af3ec956d4b62330a16c66