tests: ignore Jinja variables inside raw blocks in variable definitions check

- Added regex masking to skip {{ var }} usages inside {% raw %}…{% endraw %} blocks.
- Simplified code by removing redundant comments.
- Cleaned up task file for XWiki role by removing outdated note.

Ref: https://chatgpt.com/share/68cd2558-e92c-800f-a80a-a79d3c81476e

roles/web-app-xwiki/tasks/04_extensions.yml

@@ -9,7 +9,6 @@
 #
 # Notes:
 #  - We print machine-readable markers so Ansible can assert deterministically.
-#  - We protect XWiki's {{groovy}} wiki macro from Jinja by using {% raw %}…{% endraw %}.
 
 - name: "XWIKI | Build Groovy installer code from static file (base64 payload)"
   vars: