Fix CA1853: Unnecessary call to 'Dictionary.ContainsKey(key)'

Author: bkoelman

src/JsonApiDotNetCore.OpenApi.Client.NSwag/JsonApiClient.cs

@@ -147,10 +147,8 @@ public void RegisterDocument(object document, AlwaysIncludedAttributes alwaysInc
 
         public void UnRegisterDocument(object document)
         {
-            if (_alwaysIncludedAttributesByDocument.ContainsKey(document))
+            if (_alwaysIncludedAttributesByDocument.Remove(document))
             {
-                _alwaysIncludedAttributesByDocument.Remove(document);
-
                 Type documentType = document.GetType();
                 _documentsByType[documentType].Remove(document);