Default image is not loaded after removing media

We'll need to check if clicking the button triggers the appropriate Redux state changes.

There's some trickiness here (surprise!) because all of the current redux-updating is based on changes to input values, but when an item is removed via media library, this is reflected in the form/ui by removing the correspnding hidden <input /> that represents the selection.

I have some ideas on how to deal with this...

Current MR gets us closer to fixing it. Currently works best when the UI is loaded and the image prop already has media.

It is still buggy when new media is added and then removed. I assume it's because the component is now removed-element aware, but there isn't yet a full equivalent for additions

wim leers → credited f.mazeikis → .

@f.mazeikis re-discovered this same bug. @longwave is going to update the media-library.cy.js e2e test.

During pair (triple?) debugging we discovered that the client-side model never got updated. Our going theory is that the mediaSelection client-side transform added in 📌 Move clientside assumptions about prop form data shape into a series of prop specific transforms Active is not firing when removing an image.

Rebased and added assertions to media-library.cy.js to demonstrate the issue. The canvas starts with a sample image inserted, which we assert correctly, then the Remove button is clicked, which (I believe) should fall back to the example image for the component - but this doesn't happen at the moment so the test fails.

Removed the SDC changes, as per Wim we can use image-optional-with-example-and-additional-prop for testing here.

There is something wrong with the changes to the frontend in this MR, as this now has the same result as 🐛 SDCs with optional images without examples cannot be placed Active when testing manually with image-optional-with-example-and-additional-prop - as soon as I select a valid media entity then the form errors out with a 400 error because the prop is missing. I've tried making some changes in the frontend code but I'm not sure what I'm doing or where it's going wrong so assigning to @bnjmnm for more investigation.

https://git.drupalcode.org/project/experience_builder/-/blame/0.x/ui/src... is the likely cause (disclaimer didn't check the MR)
When we click remove there's no new elements in the ajax response and hence nothing to trigger the model update via this event