Refactor Field components with const arrow functions (#1261)

## Summary
- convert all remaining Field components to const arrow functions
- document the refactor in the CHANGELOG

## Testing
- `npm run lint`
- `npm run build`


------
https://chatgpt.com/codex/tasks/task_e_68684db1b6b88331837307a54e3f9dc1

src/components/FieldComment.tsx

@@ -10,29 +10,31 @@ type FieldCommentInternalProps = {
   error: {message: string}
 } & WithTranslation;
 
-class FieldCommentInternal extends React.Component<FieldCommentInternalProps> {
-  render() {
-    const t = this.props.t;
-    const fieldSpec = {
-      doc: t("Comments for the current layer. This is non-standard and not in the spec."),
-    };
+const FieldCommentInternal: React.FC<FieldCommentInternalProps> = (props) => {
+  const t = props.t;
+  const fieldSpec = {
+    doc: t(
+      "Comments for the current layer. This is non-standard and not in the spec."
+    ),
+  };
 
-    return <Block
+  return (
+    <Block
       label={t("Comments")}
       fieldSpec={fieldSpec}
       data-wd-key="layer-comment"
-      error={this.props.error}
+      error={props.error}
     >
       <InputString
         multi={true}
-        value={this.props.value}
-        onChange={this.props.onChange}
+        value={props.value}
+        onChange={props.onChange}
         default={t("Comment...")}
         data-wd-key="layer-comment.input"
       />
     </Block>
-  }
-}
+  );
+};
 
 const FieldComment = withTranslation()(FieldCommentInternal);
 export default FieldComment;