DOCSP-49360 Remove extra comma in X509 code example (#605)

Author: stephmarie17

source/fundamentals/authentication/x509.txt

@@ -121,7 +121,7 @@ see the corresponding syntax:
              },
              UseTls = true,
              Server = new MongoServerAddress("<hostname>"[, "<port>"]),
-             Scheme = ConnectionStringScheme.MongoDBPlusSrv, // Needed when connecting to MongoDB Atlas
+             Scheme = ConnectionStringScheme.MongoDBPlusSrv // Needed when connecting to MongoDB Atlas
          };
 
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