Clip display blocks in the topology pane

Prevent display blocks from overflowing outside the pane when dragged.

Flag: com.android.settings.flags.display_topology_pane_in_display_list
Bug: b/352650922
Test: drag a display block so that it would overflow outside the pane
Change-Id: I326cb28f06914f71535906a0ce3e8fc04a4cb4f3