Small fix

Author: Shadi M. El Hajj Sleiman

src/ResourceManager/ResourceManager/Commands.ResourceManager/Cmdlets/Extensions/ResourceExtensions.cs

@@ -52,7 +52,7 @@ internal static PSObject ToPsObject(this Resource<JToken> resource)
                 { "Tags", TagsHelper.GetTagsHashtables(resource.Tags) },
                 { "Plan", resource.Plan.ToJToken().ToPsObject() },
                 { "Properties", resource.Properties.ToPsObject() },
-                { "PropertiesText", resource.Properties.ToString() },
+                { "PropertiesText", resource.Properties == null ? null : resource.Properties.ToString() },
                 { "CreatedTime", resource.CreatedTime },
                 { "ChangedTime", resource.ChangedTime },
                 { "ETag", resource.ETag },