[plasma-nm] Refresh wifi networks as fast as possible
Summary:
Added a retry mechanism when scanning fails, to prevent waiting unnecessarily long for the next scan.
This usually happens when closing and reopening the applet, or when a scan was started by another component before opening the applet.
Test Plan:
- First enable debug logging, there is no UI feedback
- Tested opening/closing the applet every now and then: wifis are scanned as early as NM allows
- Tested switching to the NM KCM, then switching to the applet, then to the KCM again: wifis are always scanned as early as allowed
Reviewers: jgrulich, ngraham, Plasma
Reviewed By: jgrulich
Subscribers: davidedmundson, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D18896