[BUGFIX] Debugger output: split lines before escaping them

This fixes the issue that lines are wrapped within a HTML entity.

Resolves: #79398
Releases: master, 7.6
Change-Id: I0bf1722cb9792fea0f45421fe1f72e1932879002
Reviewed-on: https://review.typo3.org/51369


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Dominique Kreemers <dominique.kreemers@icloud.com>
Tested-by: Dominique Kreemers <dominique.kreemers@icloud.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>