Remove unused storegate container in MM digitization

Removed a SimHitCollection container that was created during MM digitization but never used. This container is most likely a forgotten about container that was originally used for HITS/DIGITS validation prior to the NSWPRDValAlg which is now used.

We decided to completely remove these calls to saving this container since users would now use the NSWPRDValAlg instead and makes saving HITS during digitization less than optimal.

Tagging @pscholer just to keep in the loop.