End ripple effect on maximized button when finished dragging

Fix: 346877247
Flag: com.android.window.flags.enable_app_header_with_task_density
Flag: com.android.window.flags.enable_themed_app_headers
Test: manual - verified the focus (ripple effect) disappear after
finished drag which started on maximized window button. Maximized button
remains functionable on long-press without drag.

Change-Id: I6f05cdc46f7aef98a856e3c39bf38f33ae1d2e4c