Desktop: Maintain selection when non-selected note is deleted

[miciasto]

Issue
The issue was raised here: forum thread

The issue is that in the note list, when a note is selected and another is deleted, the selection is changed.

In my opinion, it should not. The selection should only change if the selected note/s is deleted.

Solution
The change is implemented by adjusting the logic in the reducer's handleItemDelete. As a result, this change addresses the same issue that exists for notes, notebooks and tags.

Testing
No unit tests existed for the reducer so new unit tests are created here. These unit tests only cover the functionality affected by this change. Manual testing was done on the desktop client.

Alternative solution
An alternative solution would be to change the behaviour of the right-click action so that right-clicking on a note selects it (in addition to the usual function of displaying the context menu).

[laurent22]

Makes complete sense and works as expected. Thanks for the fix @mic704b! And also thanks for adding all these tests as it's true the reducer wasn't tested at all before, so this is definitely going to improve code quality.