MBS-6615, Improve post-upload experience:

- Hide "Select images" when uploading has started, so no new images can be added.
- Disable "Enter edit" button during upload
- Re-enable "Enter edit" after upload if upload failures have occured, hitting it again will retry failed images.
Merge remote-tracking branch 'warp-bitbucket/mbs-6615' into beta

* warp-bitbucket/mbs-6615:
  MBS-6615, Improve post-upload experience:

Past freeze at nikki's request.