Apply suggestions from code review

Co-authored-by: campersau <buchholz.bastian@googlemail.com>

Author: amaitland

CefSharp/Internals/LegacyJavaScriptObjectCache.cs

@@ -26,12 +26,7 @@ public void InsertOrUpdate(int browserId, IList<JavascriptObject> javascriptObje
         {
             foreach (var obj in javascriptObjects)
             {
-                if (cache.ContainsKey(obj.Name))
-                {
-                    cache.Remove(obj.Name);
-                }
-
-                cache.Add(obj.Name, obj);
+                cache[obj.Name] = obj;
             }
         }
 

CefSharp/Internals/PerBrowserJavaScriptObjectCache.cs

@@ -29,12 +29,7 @@ public void InsertOrUpdate(int browserId, IList<JavascriptObject> javascriptObje
 
             foreach (var obj in javascriptObjects)
             {
-                if (dict.ContainsKey(obj.Name))
-                {
-                    dict.Remove(obj.Name);
-                }
-
-                dict.Add(obj.Name, obj);
+                dict[obj.Name] = obj;
             }
         }