[TASK] Remove leftover code for db_mountpoints in ActionTask

Resolves: #81999
Releases: master,8.7
Change-Id: Ib3311a4f10d7393b41c04fd193e8614d5984f35f
Reviewed-on: https://review.typo3.org/53723


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>