chore: remove old analtyics (#2338)

Summary

  Remove Reo and RB2B analytics tracking from documentation site.

  This PR removes third-party tracking scripts from the documentation:
  - Deleted docs/_static/js/reo.js - Reo analytics tracking script
  - Deleted docs/_static/js/rb2b.js - RB2B analytics tracking script
  - Removed references to both scripts from mkdocs.yml

  Changes

  - mkdocs.yml: Removed two entries from extra_javascript configuration
  - docs/_static/js/reo.js: Deleted file
  - docs/_static/js/rb2b.js: Deleted file

  Motivation

Streamlining analytics vendors used in the documentation site. Octolane
and CommonRoom analytics remain active.

Author: jjmachan

docs/_static/js/rb2b.js

@@ -284,6 +284,4 @@ extra_javascript:
   - https://unpkg.com/mathjax@3/es5/tex-mml-chtml.js
   - _static/js/toggle.js
   - https://cdn.octolane.com/tag.js?pk=c7c9b2b863bf7eaf4e2a # octolane for analytics
-  - _static/js/reo.js # reo analytics
   - _static/js/commonroom.js # commonroom analytics
-  - _static/js/rb2b.js # rb2b analytics