Algo: Bugfix bad conversion from int64 to uint64 for TimeOffset variables

Approval/review needed from:

• @a.toia (or somebody else from STS)
• @v.singhal (or somebody else from MUCH)
• @a.bercuci (or somebody else from TRD)
• @n.herrmann (or somebody else working on the mCBM "physics oriented" analysis)
• @s.zharko
• @v.friese

=> Click on the 👍 or 👎 icons to let us know without having to change the main reviewer

Redmine: Refs #3733