ZDC: Fix for ZdcNtuple crash on RPD decoding error
In the ZDC reconstruction (with RPD enabled), RpdSubtractCentroidTool will exit without writing decorations if there is a decoding error in any RPD LUCROD or, depending on the tool's configuration, ZDC LUCROD. Therefore, the existence of these decorations must be checked by any downstream tool wanting to read them. This MR restores this check (removed in !75782 (merged)) and thus fixes crashes from ZdcNtuple when there is an RPD decoding error and writing centroid branches is enabled.
Edited by Mason Ray Housenga