Migrate WindowContext#onConfigurationChanged to ClientTransaction (7/n)

1. Introdce WindowContextInfo to store info that we want to pass for
WindowContext.
2. Update #attachToWindowToken to be consistent with
   #attachToDisplayArea that it also return the current WindowContext
   config.

Before, when #attachToWindowToken, the server side will trigger an
onConfigurationChanged to the WindowContext. Now, this will be done in
the client side by post to the main thread so it doesn't change the
client side behavior.

Bug: 290876897
Test: atest FrameworksCoreTests:WindowTokenClientControllerTest
Change-Id: I7655ac454a941a795d519351de4741778c514d82