Bump chardet from 5.2.0 to 7.1.0 in /demos

Bumps [chardet](https://github.com/chardet/chardet) from 5.2.0 to 7.1.0.
- [Release notes](https://github.com/chardet/chardet/releases)
- [Changelog](https://github.com/chardet/chardet/blob/main/docs/changelog.rst)
- [Commits](chardet/chardet@5.2.0...7.1.0)

---
updated-dependencies:
- dependency-name: chardet
  dependency-version: 7.1.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

demos/moderator_bot/requirements-dev.txt

@@ -4,7 +4,7 @@ async-timeout==5.0.1
 atomicwrites==1.4.1
 attrs==25.4.0
 certifi==2026.1.4
-chardet==5.2.0
+chardet==7.1.0
 idna==3.11
 importlib-metadata==0.23 ; python_version < '3.8'
 joblib==1.5.3