Media library field modal should not close after clicking the "Insert selected" buttom if there is no image selected

I wonder if the modal should actually have a Cancel button to avoid this.

I also noticed that if you do this:

1. Create node bundle with required media field, e.g. 'Featured image'

Then when inserting new:

1. Open media library for 'Featured image'
2. Change mind and decide to do later, so click 'Insert selected' to close
3. Add title, body, etc
4. Select a 'Featured image' this time from Media Library
5. Save node

Then message is shown 'No items selected' (as well as successfully creating the Node) as it seems the media library 'cancel' did not trigger a form refresh, so the 'No items selected' stayed in the messenger queue even though a Media Library selection was actually made in step 4 above.

So I think possible solutions here:

1. Ensure that an effective 'Cancel' still triggers form refresh so 'No items selected' message is shown at appropriate time
2. Avoid showing 'No items selected' validation until full node save; ie, skip validation in the subform and only apply at form level
3. Provide a Cancel button

(on decision, update issue summary with standard template + proposed solution)