update file icons to use img instead of svg (#5709)

Author: hozefaj

src/components/PrimaryPanes/SourcesTree.js

@@ -217,7 +217,7 @@ class SourcesTree extends Component<Props, State> {
         ts: "typescript"
       }[getExtension(source)];
       return sourceType ? (
-        <Svg className="source-icon" name={sourceType} />
+        <img className={sourceType} />
       ) : (
         <img className="file" />
       );