Disables bubble drop targets for notification drag

Added intent marker for cases when drag is started from the notification

Fixes: 427242076
Flag: EXEMPT bugfix
Test: Manual. Drag notification out, bubble drop targets did not appear.
Dragged taskbar icon in app to use shell drag, the bubble drop target
appeared as expected.

Change-Id: I98343aa0b5ea2ad4ab5d3bbc6ceb7832b4ce0b95