Wait more time for activity start.

- Looks like 5 seconds is too short on some emulator devices.
- Makes sure that the app is installed and enabled.

Bug: 185483743
Bug: 185576411
Test: atest UpdatableSystemFontTest#launchApp --rerun-until-failure
Change-Id: Ibc1dba9f4b2b3c694e186798f65a456e712cba9e