Do not shrink topology pane after a drag

Changing the height of the pane causes UI elements below it to shift
around. Allow it to grow when needed but do not shrink once it has
grown.

Test: atest TopologyScaleTest.kt
Flag: com.android.settings.flags.display_topology_pane_in_display_list
Bug: b/352650922
Change-Id: I1a3e0ab77b05c5a4337e3e8ab865a974eb1faeda