Have made the SetDefaultDimensions smaller by removing the check on the global DefaultDimensions and Instead checking if the passed variable is empty if so return so we don't delete the default, other wise set the Default to the passed ones

Author: EgressGlynn

libraries/src/AWS.Lambda.Powertools.Metrics/Model/MetricDirective.cs

@@ -199,12 +199,10 @@ internal void AddDimension(DimensionSet dimension)
     /// <param name="defaultDimensions">Default dimensions list</param>
     internal void SetDefaultDimensions(List<DimensionSet> defaultDimensions)
     {
-        if (!DefaultDimensions.Any())
-            DefaultDimensions = defaultDimensions;
-        else
-            foreach (var item in defaultDimensions)
-                if (!DefaultDimensions.Any(d => d.DimensionKeys.Contains(item.DimensionKeys[0])))
-                    DefaultDimensions.Add(item);
+        if (!defaultDimensions.Any())
+            return;
+
+        DefaultDimensions = defaultDimensions;
     }
 
     /// <summary>