Changed Content Catpure workflow so it notifies when multiple changes are made.

Prior to this change, it sent a pair TYPE_INITIAL_VIEW_TREE_APPEARING and
TYPE_INITIAL_VIEW_TREE_APPEARED after the initial layout, then it would send invididual events for
the views appeared / disappeared.

This change improves the workflow by also sending this pair of events after each change, which lets
the service know that a bunch of changes were made at the same layout pass.

Test: atest CtsContentCaptureServiceTestCases # which was updated to listen to the new events
Test: m update-api

Bug: 125395044

Change-Id: Ied9def9c95dd0f7711f59bccb2cc89a766fdc36b