Fix flaky cross-profile test by waiting for broadcasts

Fix CrossProfileAppsTargetUserTest#testCanStartMainActivity by waiting for the
test app installation to fully complete with waitForBroadcastIdle().

Test: atest CtsDevicePolicyManagerTestCases:com.android.cts.devicepolicy.CrossProfileAppsHostSideTest#testManagedProfileToPrimaryUser
Test: atest CtsDevicePolicyManagerTestCases:com.android.cts.devicepolicy.CrossProfileAppsHostSideTest#testPrimaryUserToManagedProfile
Fixes: 132703619
Change-Id: I8103ef7e0279147c8c91db2b49493a194002447c
1 file changed