don't load model if it has already been loaded

ui/shared/monaco/CodeEditor.tsx

@@ -43,7 +43,10 @@ const CodeEditor = ({ data }: Props) => {
     monaco.editor.defineTheme('blockscout-dark', themes.dark);
     monaco.editor.setTheme(colorMode === 'light' ? 'blockscout-light' : 'blockscout-dark');
 
-    data.slice(1).forEach((file) => {
+    const loadedModelsPaths = monaco.editor.getModels().map((model) => model.uri.path);
+    data.slice(1)
+      .filter((file) => !loadedModelsPaths.includes(file.file_path))
+      .forEach((file) => {
         monaco.editor.createModel(file.source_code, 'sol', monaco.Uri.parse(file.file_path));
       });
   // componentDidMount