Wait more time to complete activity launch

This CL address flakiness by following change
- Add "-W" option to "am start-activity" to wait first screen draw
- Increase timeout time from 10ms to 50ms

Bug: 405229719
Test: atest UpdatableSystemFontTest#launchApp_afterUpdateFont
Flag: TEST_ONLY
Change-Id: Ie66a2347de21cdf9e369cc80de8bbcb26f326541