Fix support for extras in micropip. ### Description

Fix for https://github.com/pyodide/pyodide/issues/2535

### Checklists

- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests

package:
  name: micropip
  version: "0.1"
requirements:
  run:
    - pyparsing
    - packaging
    - distutils # TODO: remove once there is a release with https://github.com/pypa/packaging/pull/396
source:
  path: src
test:
  imports:
    - micropip

package:
  name: micropip
  version: "0.1"
requirements:
  run:
    - pyparsing
    - packaging
    - distutils # TODO: remove once there is a release with https://github.com/pypa/packaging/pull/396
source:
  path: src
test:
  imports:
    - micropip
