Small fixes in RIO_OnTrackCreator and MuonClusterOnTrackCreator

Merged Patrick Scholer requested to merge pscholer/athena:MMClusterOnTrackCreator_fixes into 21.3

This MR applies fixes in the RIO_OnTrack messaging which were missed in !34440 (merged). I also reverts one change which was introduced in the MMCLusterOnTrackCreator in the same MR. In the sweep to master of the original MR these things have already been fixed. Therefore this MR is only alsoTargeting:21.9

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