test: fix MongoClientFactoryTests mock.

Author: lucianareginalino

test/Liquid.Repository.Mongo.Tests/MongoClientFactoryTests.cs

@@ -20,6 +20,7 @@ public MongoClientFactoryTests()
         {
             var options = new MongoRunnerOptions
             {
+                UseSingleNodeReplicaSet = false,
                 AdditionalArguments = "--quiet", 
                 KillMongoProcessesWhenCurrentProcessExits = true
             };