[!!!][TASK] Remove obsolete message about old-style workspaces

This was used in 4.5 back then when migrating to draft workspace
etc. The upgrade wizard in the install tool does not even exist
anymore, so the functionality is completely removed.

Resolves: #77591
Releases: master
Change-Id: Ibfe3f4cec232597c395ae2279f8bb4133c9eb7af
Reviewed-on: https://review.typo3.org/49540


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>