Fix unable starting home on an empty display

- Using the activity type of starting activity if caller
  did not specified it in ActivityOptions.
- Avoid reusing home activity on other displays while
  starting home with component specified.
- Start focused activities on all displays after process
  attached.

Bug: 119844270
Test: atest ActivityManagerMultiDisplayTests
Change-Id: I10cec4dc47626319788a306fa672fa597d1746b9