feat: update figure label and max heading level

Update the figure label element from "label" to "h4" in figure.tsx.
Also, adjust the max heading level from 4 to 5 in content-to-jsx.tsx.

src/components/atoms/figure/figure.tsx

@@ -35,7 +35,7 @@ export const Figure = ({
   return (
     <div className="figure-container">
       <figure className="figure" {...(id && { id })}>
-        {label && <label className="figure__label">{label}</label>}
+        {label && <h4 className="figure__label">{label}</h4>}
         {content}
         {caption && <figcaption ref={captionRef} className={`figure__caption${expanded ? ' figure__caption--expanded' : ''}`}>{caption}</figcaption>}
       </figure>

src/utils/content-to-jsx.tsx

@@ -82,7 +82,7 @@ export const contentToJsx = (content?: Content, options?: Options, index?: numbe
     case 'Date':
       return <time key={index}>{ contentToJsx(content.content, options)}</time>;
     case 'Figure':
-      return <Figure key={index} id={content.id} caption={contentToJsx(content.caption, { ...options, maxHeadingLevel: 4 })} label={content.label} content={contentToJsx(content.content, options)} />;
+      return <Figure key={index} id={content.id} caption={contentToJsx(content.caption, { ...options, maxHeadingLevel: 5 })} label={content.label} content={contentToJsx(content.content, options)} />;
     case 'ImageObject':
       if (!content.contentUrl) {
         return '';