fix: Add wrapping div for scrollytelling map and chapters (#1437)

**Related Ticket:** Fix #1418

### Description of Changes
Since the legacy instance was using a lazyload-wrapper this wasn't
necessary*, but for instances not using this approach, the additional
wrapping div is actually required to build the layout as intended. It
doesn't hurt the legacy either.

\* The LazyLoad component from 'react-lazyload' creates a wrapping div
with `class="lazyload-wrapper "`


### Validation / Testing
Go to a story, make sure you can scroll down all the way to see text
content below the scrollymap, as well as map comparison blocks.
Corresponding deploy preview from next-veda-ui:
https://deploy-preview-43--veda-ui-next-test.netlify.app/stories/air-quality-and-covid-19

Author: AliceR

app/scripts/components/common/blocks/scrollytelling/index.tsx

@@ -358,7 +358,7 @@ function Scrollytelling(props) {
     activeChapterLayerData ?? {};
 
   return (
-    <>
+    <div>
       <ScrollyMapContainer topOffset={topOffset || 0}>
         {areLayersLoading && <MapLoading />}
 
@@ -470,7 +470,7 @@ function Scrollytelling(props) {
         </Map>
       </ScrollyMapContainer>
       <TheChapters>{children}</TheChapters>
-    </>
+    </div>
   );
 }