JetForwardJvtTool: small fix for PFlow fJVT

Small fix toward the upcoming fJVT recommendations.

PFlow central jets were flagged as 'failing' the fJVT cut, requiring users to select themselves the forward jets for which to retrieve the flag. This is now done as for EMTopo fJVT, with the jets outside the tagging range flagged as 'passing fJVT', so that users can simply retrieve the fJVT flag for all jets without any issue.

Also added the missing 'fJvt' decoration to PFlow jets. This is just a copy of the 'DFCommonJets_fJvt' moment, but allows users to retrieve the moment for both the EMTopo and PFlow jet collections with the same variable name.