Detect when user wanted to drag vs. click

In order to avoid sending a new topology to DisplayManager
unnecessarily, which could cause some disruptive visual effect, don't do
anything if the drag was both (a) brief and (b) did nto deviate from
start position.

Flag: com.android.settings.flags.display_topology_pane_in_display_list
Test: DisplayTopologyPanePreferenceTest
Test: manual - quickly drag as few pixels as possible and verify the block moved back after drag, with no scale change
Bug: b/352648432
Change-Id: I29ffb51c54c9dbac970149cffd86a8027f0a42f5