Add flag to not use the immediate kotlin coroutine dispatcher

We had evidences using the immediate dispatcher might be causing additional work, expecially during "combine", as it was triggered inside the doFrame with intermediate values multiple times instead of once after the frame only.

Bug: 411091082
Test: SysUI boots
Flag: com.android.systemui.do_not_use_immediate_coroutine_dispatcher
Change-Id: I3d6cf46c550b85af666a9e95c94a78b674b25e77