Deprecate drag-corner-to-resize-pip on phones

This feature is never in production for phones. Note that the
resize_handle is still in use in ArcPipMenuIconAlgorithm and therefore
it's kept as it is.

Bug: 323420420
Flag: N/A
Test: atest PinnedStackTests PipResizeGestureHandlerTest
Test: m -j ArcSystemUI
Change-Id: I9ddcabe68c29e15ba0483b00b0db00ae25f3ff6d