[MWPW-184752] Ensure carousel first slide img load

[overmyheadandbody]

On mobile devices, additional logic is executed for the carousel, to ensure slides have a balanced height. However, this logic is currently able to execute even before images have finished loading. This PR waits for the images from the first slide to load before executing any additional height logic.

To reproduce the original issue, use a viewport below 900px and throttle the network via the Network or Performance tabs in Developer tools to 3G/Slow 4G.

Screenshots

Before	After

Resolves: MWPW-184752

Test URLs:

• Before (original issue): https://main--cc--adobecom.aem.page/creativecloud
• After (original issue): https://main--cc--adobecom.aem.page/creativecloud?milolibs=carousel-image-load
• Before (Kitchen sink): https://main--milo--adobecom.aem.page/docs/library/kitchen-sink/carousel
• After (Kitchen sink): https://carousel-image-load--milo--adobecom.aem.page/docs/library/kitchen-sink/carousel
• Before (Mweb carousel): https://main--milo--adobecom.aem.page/docs/library/kitchen-sink/carousel-mweb
• After (Mweb carousel): https://carousel-image-load--milo--adobecom.aem.page/docs/library/kitchen-sink/carousel-mweb

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Commits

• 71d1339 ✅ (latest)

[mokimo]

Few questions, knowing that you usually consider a lot of use-cases, those might already have been considered!

[mokimo]

Thanks for the detailed answers and providing context - am fully on your side with your assumptions. We can still re-visit if QEs/others raise some issues.

[github-actions]

Reminder to set the Ready for Stage label - to queue this to get merged to stage & production.

[biljana-cvijanovic]

Validated. Testing details https://jira.corp.adobe.com/browse/MWPW-184752

[github-actions]

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