Sweeping !21144 from 21.3 to 21.9. Modify MM_Digitization to use MMSimHit in MM digits production. (ATLASSIM-3755)

Atlas Nightlybuildrequested to merge
cherry-pick-2e7e4fb522-21.9 into 21.9

Modify MM_Digitization to use MMSimHit in MM digits production. (ATLASSIM-3755)

See merge request !21144 (merged)

Merge request reports