docs: remove irrelevant changelog entry (#628)

## Summary
- Remove the "Update black to fix ReDoS vulnerability" entry from the
v2.4.1 changelog, as it is not relevant to this package

## Test plan
- [x] Verify the changelog entry is removed
- [x] Verify surrounding entries are intact

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: vdusek

CHANGELOG.md

@@ -21,7 +21,6 @@ All notable changes to this project will be documented in this file.
 
 ### 🐛 Bug Fixes
 
-- Update black to fix ReDoS vulnerability ([#582](https://github.com/apify/apify-client-python/pull/582)) ([aae2eb9](https://github.com/apify/apify-client-python/commit/aae2eb9f5aeda0c7274285b9aaab3c73550bcad6)) by [@B4nan](https://github.com/B4nan)
 - Only include Actor standby when at least one field is provided ([#597](https://github.com/apify/apify-client-python/pull/597)) ([7112c09](https://github.com/apify/apify-client-python/commit/7112c09ceab0d87a0bd0caecabea634c70f63b8c)) by [@vdusek](https://github.com/vdusek), closes [#595](https://github.com/apify/apify-client-python/issues/595)
 - Add missing tagged_builds parameter to Actor update method ([#596](https://github.com/apify/apify-client-python/pull/596)) ([6210e80](https://github.com/apify/apify-client-python/commit/6210e80fc5037d57c969a16458c13b68b61ddd07)) by [@vdusek](https://github.com/vdusek), closes [#585](https://github.com/apify/apify-client-python/issues/585)