What?

Convert the value of the parameter include into a string when it's
a number.

Why?

fixes: #27771

This bug is backwards compatibility issue

How?

Testing Instructions

1. Make a clean Wordpress installation
2. Upload an image to the media library and take note of it's post_id (let's say it's 6)
3. Open the page editor and the Javascript console then type in wp.data.select('core').getEntityRecords('postType', 'attachment', { include: 6 })
4. wp.data.select('core').getEntityRecords('postType', 'attachment', { include: '6' })
5. steps 3 and 4 should return the same result : the attachment data

Head's up: steps 3 or 4 could return null first, and then the second time the attachment data after the request had resolved.

Screenshots or screencast

@adamziel might be a good person to take a look at this one if he has time alongside his duties as Editor release lead.

I cherry picked this change into wp/6.0 branch to be included in WordPress 6.0 Beta 4 on Monday: 0bfa48c