Correct mappings validator clause

Author: acoumb

src/Umbraco.Forms.Integrations.Commerce.EMerchantPay/Services/MappingService.cs

@@ -35,7 +35,7 @@ public bool TryParse(string mappings, out List<Mapping> result)
 
             result = JsonConvert.DeserializeObject<List<Mapping>>(mappings);
 
-            return result.Count == configMappings.Count() + 1 && result.Any(p => p.CustomerProperty == nameof(MappingValues.Email));
+            return result.Count == configMappings.Count() && result.Any(p => p.CustomerProperty == nameof(MappingValues.Email));
         }
     }
 }