Image dimensions are not set

[a-rbsn]

Discussed in https://github.com/craftcms/redactor/discussions/405

As someone using element-api to get rich-text content, it would be useful to have image width and height available even so we know the ratio of the image to prevent jumping.

^{Originally posted by nicbou June 22, 2021}

Description

When inserting an image with Redactor, the image does not have width and height attributes. Those are important to prevent the content from jumping around while it loads, especially with lazyloaded images.

Steps to reproduce

1. Insert an image
2. It does not have width and height attributes