Bump langchain-text-splitters from 1.1.1 to 1.1.2 in /backend

Bumps [langchain-text-splitters](https://github.com/langchain-ai/langchain) from 1.1.1 to 1.1.2.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](https://github.com/langchain-ai/langchain/compare/langchain-text-splitters==1.1.1...langchain-text-splitters==1.1.2)

---
updated-dependencies:
- dependency-name: langchain-text-splitters
  dependency-version: 1.1.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

backend/requirements-min.txt

@@ -48,7 +48,7 @@ openai
 langchain==1.2.10
 langchain-community==0.4.1
 langchain-classic==1.0.1
-langchain-text-splitters==1.1.1
+langchain-text-splitters==1.1.2
 
 fake-useragent==2.2.0
 

backend/requirements.txt

@@ -52,7 +52,7 @@ google-genai==1.66.0
 langchain==1.2.10
 langchain-community==0.4.1
 langchain-classic==1.0.1
-langchain-text-splitters==1.1.1
+langchain-text-splitters==1.1.2
 
 fake-useragent==2.2.0
 chromadb==1.5.2