windowswitchers: make window titles accessible
All window switchers in kdeplasma-addons except sidebar currently do not correctly informs screen readers of the selected window's title, making them inaccessible to blind users and others requiring a screen reader. This is mostly because the delegates for the respective views are components that do not have a proper accessible.name set, and/or because the view doesn't actually have focus and therefore screen readers are not kept up to date as it changes.
This change properly sets Accessible.name for the delegates, and gives actual focus to the view, making the switchers usable for those relying on screen readers.
I'd like to propose this for cherry-picking into 6.3, as it's an accessibility bugfix. That said, the default switcher (and sidebar) are already read out, so there are options for screen reader users already, so I'd also be ok with delaying it to 6.4