Summary:
If we changed containment with the config open, relaunch the config
dialog but for the new containment.
This provides a somewhat seamless changing desktop types.
BUG: 355642
Test Plan:
Opened config, changed type, hit apply -> dialog was replaced
Opened config, changed activity -> Dialog was replaced
Opened config, Closed Config, changed activity -> Nothing happened
Reviewers: #plasma, mart
Reviewed By: mart
Subscribers: mart, plasma-devel
Tags: #plasma
Differential Revision: https://phabricator.kde.org/D4086