Implement getCurrentWindowLayoutInfo() API.

This commit implements the getCurrentWindowLayoutInfo() API in window
extension v9, targeting the 25Q2 release. It enables access to window
layout information during the onCreate lifecycle callback. Check
ag/29908303 for API definition and more details.

Bug: 337820752
Flag: com.android.window.flags.wlinfo_oncreate
Test: atest WMJetpackUnitTests:WindowLayoutComponentImplTest
Change-Id: I43403a633e9a396ab9ce2cc1aef4ff4c70547573