[TASK] Apply uglify to TypeScript builds

The Grunt task `copy:ts_files` now modifies the uglify configuration
on-the-fly to minify the files compiled by TypeScript.

Resolves: #83251
Releases: master
Change-Id: I11faf7ae39f2605b4e8a8a6972f4f16c4b80138f
Reviewed-on: https://review.typo3.org/55639


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Benjamin Kott <benjamin.kott@outlook.com>
Tested-by: Benjamin Kott <benjamin.kott@outlook.com>