fix(edt): considering power saver mode when updating the force invert type

Since the power saver dark theme override is not captured in
mComputedNightMode, we need to consider this case when updating the
force invert type.

Bug: 442998674
Test: atest UiModeManagerServiceTest
Test: manually verifying through the reproduce steps
Flag: android.view.accessibility.force_invert_color
Change-Id: I1193550a142044e5c290c44344c4d7d50dc70be5