[MUON] fixed normalization of tracks histograms (#1612)

The loading of the GRPECS object needs to be enabled in order to retrieve
the correct value of orbits/TF, otherwise the default value of 128
is used. The orbits/TF is used for the absolute normalization of the histograms.

Author: aferrero2707

DATA/production/qc-async/mch-tracks.json

@@ -41,7 +41,7 @@
                 },
                 "grpGeomRequest": {
                     "geomRequest": "Aligned",
-                    "askGRPECS": "false",
+                    "askGRPECS": "true",
                     "askGRPLHCIF": "false",
                     "askGRPMagField": "false",
                     "askMatLUT": "false",