[BUGFIX] Restore update wizard to add TER repository in EM

This adds the update wizard again for TER repository in EM.

Resolves: #72917
Releases: master, 7.6
Change-Id: I1d4d6750c1e989a4ca3fadbcf6e753555ae26f5f
Reviewed-on: https://review.typo3.org/46303


Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Reviewed-by: Markus Sommer <markussom@posteo.de>
Tested-by: Markus Sommer <markussom@posteo.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>