Manifest upload UI status bleeds into other orgs
Description of problem:
When uploading a manifest in an Org, and then switching to another org to do the same, user is greeted with the manifest upload status bar from the previous org.
Version-Release number of selected component (if applicable):
6.4.0 snap 10
Steps to Reproduce:
1. Create two orgs, "Org ABC" and "Org 123"
2. Switch to Org ABC
3. Content > Subscriptions > Manage Manifest
4. Upload Manifest; observe the expected status bar UI
5. While manifest is uploading, switch to Org 123
6. Content > Subscriptions > Manage Manifest
The "Uploading %" status UI from the first org appears on the page of the second org.
There should be no evidence of what's going on in one org, in a separate one. Org manifest handling should be wholly independent and opaque across orgs.