wp-env: Fix chown cannot access 'wp-config.php'

[ribaricplusplus]

Description

IMPORTANT: Do not merge this until docker-library/wordpress#587 gets pushed to Docker Hub. Update: The change has been pushed to Docker Hub and this PR is safe to merge.

This PR fixes #29814. We used to manually run chown on wp-config.php because Docker Hub Wordpress image would create it with root being the owner, which means we can't access wp-config.php with wp cli and that caused problems. The problem with this manual solution was that there was a race condition: After containers start, the files are not actually ready, and if we run chown before files are copied, the issue #29814 happens.

Since the permission problem is now solved at the root, in the Docker Hub image in the aforementioned PR, there's no longer any need for manually doing chown, so this PR removes that.

How is this tested

EDIT: Now that the Docker Hub image has been updated, this PR can be tested by simply getting it locally and trying wp-env start

I manually built the WordPress image from the aforementioned PR docker-library/wordpress#587 and used this PR for wp-env. If you want to test the same way, it will be necessary to change FROM in the Dockerfile to the image that you manually build, that is here:

gutenberg/packages/env/lib/init-config.js

Lines 106 to 108 in 8a43a90

	return `FROM ${ image }

[noahtallen]

Some related issues this might solve (or open a path towards solving): #22515, #28201, #29929

[ribaricplusplus]

The needed change to Docker Hub wordpress image has been pushed: docker-library/official-images#9833

This PR can now be merged (as far as I'm concerned).

[noahtallen]

I did a lot of testing on this, and everything is working very well (both with and without specifying core sources). Thanks for investigating this!