Ignore the prefModeId only for PiP windows, rather than all non-focussed

windows.

Ignoring the pref mode Id for all non-focussed window causes issues in
case of secondary displays. This will lead to unncessary mode switches
when focus switches. Also, this would ignore the vote of main window on
seconsary display if current focus is with primary display.

Bug: 243147584
Test: atest DisplayTest#testRefreshRateSwitchOnSecondaryDisplay
Change-Id: I760a6e7a568f882361a8d323d27d4e92ee2023ae