[TASK] Remove old class files from ext:t3editor

Change-Id: Id7cd8fdaecf663462b8d02a4bf2ca272293cea4f
Resolves: #55792
Related: #47756
Releases: 6.2
Reviewed-on: https://review.typo3.org/27460
Reviewed-by: Marcin Sągol
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters