[MS] MSUnmerged cycle failing to fetch data from Rucio ConMon
**Impact of the bug**
MSUnmerged

**Describe the bug**
While checking the MSUnmerged production logs from today, I noticed the following error [1], which keep happening in every cycle.

Reason seems to come from the fact that:
1. MSUnmerged defaults Rucio ConMon url to its testbed instance: https://github.com/dmwm/WMCore/blob/master/src/python/WMCore/MicroService/MSUnmerged/MSUnmerged.py#L96
2. And the production service configuration is missing this `rucioConMon` attribute: https://gitlab.cern.ch/cmsweb-k8s/services_config/-/blob/prod/reqmgr2ms-unmerged/config-unmerged.py#L85

**How to reproduce it**
Testbed Rucio ConMon response isn't a valid JSON object: https://cmsweb-testbed.cern.ch/rucioconmon/WM/stats

**Expected behavior**
Fix the service configuration according to the service class (pre-production MSUnmerged talks to pre-production external services; and production to production)

**Additional context and error message**
[1]
```
2021-08-03 08:10:11,637:INFO:MSManager: Starting the unmerged thread...
2021-08-03 08:10:11,638:DEBUG:RucioConMon: Fetching data from /WM/stats, with args None
2021-08-03 08:10:11,638:DEBUG:Service: Data is from the Service cache
2021-08-03 08:10:11,638:ERROR:MSUnmerged: Unknown exception while running MSUnmerged thread Error: Expecting value: line 1 column 1 (char 0)
Traceback (most recent call last):
  File "/data/srv/HG2108g/sw/slc7_amd64_gcc630/cms/reqmgr2ms/0.5.1.pre5/lib/python3.8/site-packages/WMCore/MicroService/MSUnmerged/MSUnmerged.py", line 126, in execute
    self.rseConsStats = self.rucioConMon.getRSEStats()
  File "/data/srv/HG2108g/sw/slc7_amd64_gcc630/cms/reqmgr2ms/0.5.1.pre5/lib/python3.8/site-packages/WMCore/Services/RucioConMon/RucioConMon.py", line 85, in getRSEStats
    rseStats = self._getResult(uri, callname='stats')
  File "/data/srv/HG2108g/sw/slc7_amd64_gcc630/cms/reqmgr2ms/0.5.1.pre5/lib/python3.8/site-packages/WMCore/Services/RucioConMon/RucioConMon.py", line 66, in _getResult
    results = json.loads(results)
  File "/data/srv/HG2108g/sw/slc7_amd64_gcc630/external/python3/3.8.2-comp/lib/python3.8/json/__init__.py", line 357, in loads
    return _default_decoder.decode(s)
  File "/data/srv/HG2108g/sw/slc7_amd64_gcc630/external/python3/3.8.2-comp/lib/python3.8/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/data/srv/HG2108g/sw/slc7_amd64_gcc630/external/python3/3.8.2-comp/lib/python3.8/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
```
diff --git a/src/python/WMCore/MicroService/MSUnmerged/MSUnmerged.py b/src/python/WMCore/MicroService/MSUnmerged/MSUnmerged.py
index d03fa11fa..38d84a151 100644
--- a/src/python/WMCore/MicroService/MSUnmerged/MSUnmerged.py
+++ b/src/python/WMCore/MicroService/MSUnmerged/MSUnmerged.py
@@ -93,7 +93,6 @@ class MSUnmerged(MSCore):
         self.msConfig.setdefault("limitFilesPerRSE", 200)
         self.msConfig.setdefault("skipRSEs", [])
         self.msConfig.setdefault("rseExpr", "*")
-        self.msConfig.setdefault("rucioConMon", "https://cmsweb-testbed.cern.ch/rucioconmon/")
         self.msConfig.setdefault("enableRealMode", False)
         self.msConfig.setdefault("dumpRSE", False)
         self.msConfig.setdefault("gfalLogLevel", 'normal')
['src/python/WMCore/MicroService/MSUnmerged/MSUnmerged.py']