Adding retrieval part for sTGC AsBuilt in the MuonDetectorManager
This is a follow-up MR to !53584 (merged) in order to add the lines of code needed in the MuonDetectorManager class in order to retrieve the as-built location of the sTGC strips.
Similarly with the MM case, a flag to enable as-built conditions is introduced in MuonDetectorTool. This flag triggers the instantiation of the NswAsBuilt::StgcStripCalculator in the MuonDetectorManager that lies in the Condition Store. The sTgcReadoutElements can then retrieve it to provide corrected positions along strips.