Explicitly waiting for Launcher to restart after enabling test content provider

I hope that this will prevent diagnostics that the Launcher has restated during the test.

This CL is a partial revert of ag/25428448

Bug: 314809015
Test: presubmit
Flag: N/A
Change-Id: I52f9641a5efcb67465794abca4f8ead621fad434
1 file changed