Replace default export with named exports (#1998)

## Launch Checklist

See title,
Also removed some "_" from some file names.
This is a pure refactoring, no logic changes.


 - [x] Briefly describe the changes in this PR.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/components/MapMaplibreGlFeaturePropertyPopup.tsx

@@ -63,7 +63,7 @@ type FeaturePropertyPopupProps = {
   features: InspectFeature[]
 };
 
-class FeaturePropertyPopup extends React.Component<FeaturePropertyPopupProps> {
+export class FeaturePropertyPopup extends React.Component<FeaturePropertyPopupProps> {
   render() {
     const features = removeDuplicatedFeatures(this.props.features);
     return <div className="maputnik-feature-property-popup" dir="ltr" data-wd-key="feature-property-popup">
@@ -75,6 +75,3 @@ class FeaturePropertyPopup extends React.Component<FeaturePropertyPopupProps> {
     </div>;
   }
 }
-
-
-export default FeaturePropertyPopup;