Clean up test app before starting the activity

Remove already installed test pacakges on test
start and Increase the time out for assertion as
package added/removed broadcast are pretty slow
on cf devices (permission controller update UI
based on these broadcasts)

Bug: 269730384
Bug: 275752754
Test: presubmit
Test: atest ManageStandardPermissionsFragmentTest --iterations 20
Change-Id: I88da44477b2c47dfc760ee20eb8037b1df4fa024