Run surface placement at the end of display change

It was
1. Configuration change from
   a. DC#reconfigureDisplayLocked
2. Surface placement delivers task info change from
   a. (1.a) -> sendNewConfiguration
      -> DC#updateDisplayOverrideConfigurationLocked
      -> continueWindowLayout
   or
   b. (1.a) -> performSurfacePlacement
3. Request transition

This makes 2 happen after 3, so the task info changes won't
reach shell before display transition is requested.

Also reduce unnecessary placement from (2.b).

Bug: 301420598
Test: Fold/unfold split screen. There is no split screen transition
      after display change transition.
Change-Id: I2b755db6fa2c388eb6db2bed18d298dc7c844925