[JIRAALIGN-1283] Unassigned backlog slide-out window closes when applying rank

Issue Summary

When the user clicks Apply the Rank button in the Unassigned backlog (story backlog, Kanban by iteration view), the Unassigned backlog window closes and the user has to re-open it and reapply your filters to get you back to where they were. Also, if the user elects to apply the Rank after previewing it, the changes are not saved.

Reproduces on ac10xm1.agilecraft.com

Steps to Reproduce

1. Log in to Jira Align
2. Select a Program and PI's in Tier 1 (in my case, it was Program: AgileCraft Core and PI's GNR, Atlanta, and Hardkiss)
3. Navigate to the backlog
4. Select Story Backlog
5. Click the Kanban view and select Iteration (or Sprint) view
6. On the Kanban Sprint view page, click the "Unassigned Backlog" button. This will bring up a slide-out window.
7. In the slide-out window, select a PI (optional) and a Team. This will bring up a list of stories.
8. Click Pull Rank and select "User Feature Rank to Sort Stories"
9. Click Yes to see a preview of the Rank.
10. The preview Rank appears.
11. Click Apply to apply the rank.

Expected Results

The slide out window stays open, revealing the new story rank.

Actual Results

The slide out window closes without being able to see the newly applied rank.
The user has to click on the "Unassigned Backlog" button to to bring the window back up. They also have to reapply any filters. Once this is done, they also find that the ranking they attempted to pull is not applied.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available