[kde-plasma] switch to new Breath themes
The Breath2 theme has been renamed to Breath Classic on the x86_64 side and a new Breath theme has been introduced.
We will also update to this theme in ARM, after our 21.12 release, so we have some time to test it properly before our 22.02 release.
So this issue is just a reminder, to switch our kde-plasma edition properly to the new Breath theme when we upload it to unstable branch after the 21.12 release.