Make an understandable and working documentation for DimensionControl component

[fabienlege]

I try to implement DimensionControl from official documentation (https://developer.wordpress.org/block-editor/components/dimension-control/) but the exemple provided in doc not working at all.

if you try to run the dox exemple code, you get a sublime partialRight is undefined.

If you try to replace onChange handler by console.log, you get `Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.

Check the render method of edit.`

[rmorse]

partialRight is coming from lodash - try including that in your JS

const { partialRight } = window.lodash;

or

import { partialRight } from 'lodash';

[ryanwelcher]

It looks like the docs need to be updated regardless of this issue so during that process, we can check to see if this error still happens and adjust as needed.

Change first line to import from @wordpress/element.