chore(deps): bump chromadb from 0.5.0 to 0.5.3 in /backend

Bumps [chromadb](https://github.com/chroma-core/chroma) from 0.5.0 to 0.5.3.
- [Release notes](https://github.com/chroma-core/chroma/releases)
- [Changelog](https://github.com/chroma-core/chroma/blob/main/RELEASE_PROCESS.md)
- [Commits](https://github.com/chroma-core/chroma/compare/0.5.0...0.5.3

)

---
updated-dependencies:
- dependency-name: chromadb
  dependency-type: direct:production
  update-type: version-update:semver-patch
...
Signed-off-by: dependabot[bot] <support@github.com>

backend/requirements.txt

@@ -35,7 +35,7 @@ langchain-community==0.2.0
 langchain-chroma==0.1.1
 
 fake-useragent==1.5.1
-chromadb==0.5.0
+chromadb==0.5.3
 sentence-transformers==2.7.0
 pypdf==4.2.0
 docx2txt==0.8