Update pr.yml to handle creating mdx files

[botanical]

Context

In pr.yml, we currently have a no-op for creating mdx files. Uncomment and test it.

veda-data/.github/workflows/pr.yml

Lines 214 to 223 in 57f1005

	- name: Create dataset mdx for given collections
	env:
	PUBLISHED_COLLECTION_FILES: ${{ needs.dataset-publication-and-configuration.outputs.publishedCollections }}
	run: echo "NO-OP step"
	# run: |
	# pip install -r scripts/requirements.txt
	# for file in "${PUBLISHED_COLLECTION_FILES[@]}"
	# do
	# python3 scripts/mdx.py "$file"
	# done

Acceptance Criteria

• workflow is updated to have a step that correctly creates mdx files
• relevant testing is done to ensure the step works correctly