[BUGFIX] NEWS.txt entry about removed PATH_t3lib constant

Adds information about removed PATH_t3lib constant and moved
JavaScript files from t3lib.

Resolves: #52785
Releases: 6.2
Change-Id: I366a6d8f78e034ec321872f9e6d5301093be13b6
Reviewed-on: https://review.typo3.org/25266
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters