CODEOWNERS: add WIT PM/EM reviewers to bots-related paths (#32971)

Adding the WIT PM/EM team as CODEOWNERS across all bots-related documentation paths to share review load.

Additive only — no existing owners removed.

Names added (one or more per path, based on who was already present):
- @marinaelmore
- @njustus1
- @migueldemoura
- @olipayne
- @cf-jian

Scope: 24 lines across 4 product areas:
- /docs/bots/ + 7 sub-paths
- /docs/ai-crawl-control/ + partials + changelog
- /docs/cloudflare-challenges/ + partials + changelog + directory + /public/images/precursor/
- /docs/turnstile/ + partials + release-notes + directory + glossary + images + /public/turnstile/

GitHub org access request tracked in AM-39127.

Co-authored-by: Miguel de Moura <9093796+migueldemoura@users.noreply.github.com>