Bug 1477064 - Collect PLUGIN_DRAWING_MODEL histogram data on release. r=francois, data=francois

toolkit/components/telemetry/Histograms.json

@@ -12557,6 +12557,7 @@
     "kind": "enumerated",
     "bug_numbers": [1229961],
     "n_values": 12,
+    "releaseChannelCollection": "opt-out",
     "description": "Plugin drawing model. 0 when windowed, otherwise NPDrawingModel + 1."
   },
   "DOM_SCRIPT_KIND": {