Dev Docker: add php extensions needed for unit testing and code cover…

…age (#41409)

* Add additional ext needed for WordPress [unit testing] and code coverage

* Other additions from 41057 originally

* condense the build steps in attempt to make building more reliable

* Move pnpm_home declaration to avoid docker build warning

* Update needed packages

* Re-allow rec packages

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/13064459415

Upstream-Ref: Automattic/jetpack@42477b9