Closes https://github.com/zed-industries/zed/discussions/23823

* Fixes terminal drag and drop not working after
https://github.com/zed-industries/zed/pull/23256
* Fixes project panel items drag and drop not working after selection
overhaul even earlier: now, all marked items are added to terminal on
drag and drop

Release Notes:

- Fixed terminal drag and drop, including project panel items