Support Image Widget fully in page data form

This doesn't need to block a beta since the Page entity type doesn't have an image field (only a media field), but ideally, a stable release of XB 1.0 should work with all core field widgets.

Since we are not supporting editing nodes at 1.0.0, I don't think this needs to block the release.

Diagnosis

For an input to be React-controlled, it needs to have the 'data-form-id' attribute, which is added recursively to everything in the form array in \Drupal\experience_builder\Hook\ModuleHooks::formAlter

However, inputs such as alt are not part of this array, as they are added later in a #process callback. This may be a simple as running FormIdPreRender::addAjaxAttribute at a later stage in the render process.

The 3528384-image-widget-etc MR I just pushed has a fix for the alt text field not working. The underlying problem will occur on any form element added in a #process callback.