Utilize post install Script for Composer

[ObliviousHarmony]

All Submissions:

• Have you followed the WooCommerce Contributing guideline?
• Does your code follow the WordPress' coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

This pull request adds composer install to the postinstall action for our plugins. During this work I also noticed that prepare scripts are executing on install, and as a consequence, every package is being built. This was previously necessary, but with our build orchestration tooling, we can rely on that build packages as needed. This should remove any ambiguity around having to run the composer-install executor, as well as speed up updates since they won't build packages anymore.

Closes #32652.

How to test the changes in this Pull Request:

1. Remove all node_modules and vendor folders in your cloned directory
2. Run pnpm install, it should not build any packages. It will still build the core plugin, however, due to a separate install script in composer.json.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully run tests with your changes locally?
• Have you created a changelog file by running pnpm nx affected --target=changelog?

FOR PR REVIEWER ONLY:

• I have reviewed that everything is sanitized/escaped appropriately for any SQL or XSS injection possibilities. I made sure Linting is not ignored or disabled.

[psealock]

This is testing well and changes make sense. This part though isn't actually correct:

Run pnpm install, it should not build any packages. It will still build the core plugin

WC Admin client isn't built, so only a portion of WooCommerce is useable. Unless this is on purpose and we like the extra command or we're making the decision to handle this later on when the Admin client is migrated, we could change this line to prepare.

woocommerce/plugins/woocommerce-admin/package.json

Line 35 in 463c985

"prepack": "pnpm install && pnpm run lint && pnpm run test && cross-env WC_ADMIN_PHASE=core pnpm run build",

The rest of the changes are great 👍🏽

[ObliviousHarmony]

@psealock The work that was blocking this PR has been resolved in #32804. This PR is ready now. The test failures in the E2E related tests are unrelated and going to be fixed in #32820.

[ObliviousHarmony]

Actually, with the caching @roykho added in #32725, I think I need to add an environment variable that can be set to bypass the installation. I'll check and see, since technically composer install should see that the vendor folder is there and do nothing? Do we need to check for the presence of the cache before installing?

[psealock]

Do we need to check for the presence of the cache before installing?

Composer will avoid installing if vendor/ is present and the lock file is up to date.

I think I need to add an environment variable that can be set to bypass the installation

When would you like to bypass installation? When CI actions use a cache? In that case, probably doesn't matter

[psealock]

I think it would be good to get this merged as is and address remaining questions, if any, later on.

[github-actions]

Hi @ObliviousHarmony, thanks for merging this pull request. Please take a look at these follow-up tasks you may need to perform:

• Add the release: add testing instructions label