Fix MuFastSteering to open multiple stream for different tasks

MuFastSteering updated to open multiple stream according to different workers after the "UpdateAfterFork" call. ATM the stream is created inside

0826 StatusCode MuFastSteering::findMuonSignature(const std::vector<const TrigRoiDescriptor*>& roids,
0827                                              const std::vector<const xAOD::MuonRoI*>&   muonRoIs,
0828                              DataVector<xAOD::L2StandAloneMuon>&    outputTracks,
0829                          TrigRoiDescriptorCollection&       outputID,
0830                          TrigRoiDescriptorCollection&       outputMS,
0831                          const bool                                 dynamicDeltaRpc,
0832                          const EventContext&                        ctx) const                                           const std::vector<const xAOD::MuonRoI*>&   muonRoIs,

and not inside the one with e.g. "LVL1::MuonRoI*>& muonRoIs" or the findMuonSignatureIO .

Tagging @epasqual @sshaw @rosati