[Explore] Chart property edit modal is cached when cancel edit

[rosemarie-chiu]

Only in Explore, when cancel change on chart property, it is cached. From chart list it is fine.

How to reproduce the bug

1. Explore and chart
2. Edit chart property
3. Click "Cancel" button
4. Open chart property edit modal again
5. See the change that was "cancelled"

Expected results

If I cancelled changes, it should be cancelled and not show on UI.

Actual results

Edit modal shows what I have cancelled, it is confusing

Screenshots

Environment

(please complete the following information):

• browser type and version: Chrome latest
• superset version: latest master
• any feature flags active: default feature flags combo

Checklist

Make sure to follow these steps before submitting your issue - thank you!

• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

Add any other context about the problem here.