[IncidenceTreeModel] Update UID if it was changed
Summary:
If one creates a Todo inside KOrganizer, it sets some default generated UID.
Such UID can be changed by the resource afterwards. The model should handle this case.
This patch adds a simple check: if the uid has changed inside `onDataChange, then just update the hashes.
Test Plan:
- Add a Todo to Google Tasklist
- Add a subtodo instantly (without reloading the view)
- (without patch) Subtodo is added at the top level (parent was not recognized)
- (with patch) Subtodo is added below the parent todo
Reviewers: dvratil
Subscribers: kde-pim
Tags: KDE PIM
Differential Revision: https://phabricator.kde.org/D28436