Fix starting the activity with incorrect pid/uid

Starts the activity in the same thread vs. in the frame callback.

Bug: 406763872
Test: am start-in-vsync
Flag: EXEMPT bugfix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:fca9c788b3364017b021544ec9594b43c93c9d29)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:b04474764693d7ad05c64925a271c94574c6cb11)
Merged-In: Ida3648fb8a4c7e4801b024622f7e5f1110184a0d
Change-Id: Ida3648fb8a4c7e4801b024622f7e5f1110184a0d