Correctly map the drag view position to the Workspace

The drag view needs to be mapped to the drop target which in this
case is the Workspace instead of the CellLayout

Fix: 352569050
Test: IntegrationReorderWidgetsTest
Flag: TEST_ONLY
Change-Id: I233c2b3bf0b8637f80d74d201189b2290ef59c94
1 file changed