Cherrypick needed for merge conflict with ag/18875278

Support move to a specific location on workspace for all workspaceDragSource, so other workspaceDragSource such as HomeAppIconMenuItem can be moved to a fixed location during testing to avoid ui-diff flakiess

Design doc:
https://docs.google.com/document/d/1tZWbfsv86O6UAKtHJrDBGecu-x3ac51qmWvARDg057M

Test: atest
Bug: 216189838

Change-Id: Ia6ef7338beb257d0313be17a53a9fc59ae39fdb6
(cherry picked from commit fe8fb4d1)