applets/digitalclock: only prompt if calendar plugins are different
Reason for the change
The set of enabled calendar plugins are not stored with a cfg_ property, but managed directly by the configuration page through the saveConfig function and the configurationChanged signal. This means that changing then restoring the plugin state will still consider the configuration modified and prompt the user to save or discard it.
Instead, check if the plugin state is actually different from the saved configuration, and update the unsavedChanges property accordingly.
Test plan
- open Calendar config page
- check and uncheck the same plugin
- (without) apply button enabled (with) apply button disabled
May require plasma-desktop!2927 (merged)
Screenshots or screen recordings
On request
Bugs fixed
N/A