fix a flipped sign in the MM stereo layers in TrigL2MuonSA
This MR fixes the flipped MM tilt angles in TrigL2MuonSA. Originally the wrong geometry was reported on ATLASSIM-6001, and already fixed in MuonSpectrometer packages. But it was not reflected to TrigL2MuonSA package, since the tilt angles in this package are hard-coded. The issue on TrigMuonSA was discussed on ATR-27406.