Moving test value for MM passivation test

The flag that sets the MM passivation width is now read by MuonDetectorTool (instead of MuonDetectorCondAlg), which can pass it to any MuonDetectorManager it creates. This way the effect of passivation can be tested on digitization (which uses the manager from the detector store, instead of the one from the condition store). The initial value is always 0 so that no present studies are affected. This change was described at the NSW Software and Detector Integration meeting on June 28.