Dump WindowState to InsetsSourceProvider Proto

This CL adds WindowState into InsetsSourceProvider proto. Such
that CTS can get the window actually providing the insets, instead of
guessing from the window types.

Besides, changed the insets source proto to let it use int typed insets
type, otherwise, it will be difficult to use when insets type names are
substring of others.

Test: build and check the generated files
Bug: 304398707
Change-Id: I900ead08c6531c454ba0300e8f9c0c9a5cf7384e