chore(deps): bump the python-dependencies group

Bumps the python-dependencies group in /lib/rag/layer with 2 updates: [langchain-core](https://github.com/langchain-ai/langchain) and [numpy](https://github.com/numpy/numpy).


Updates `langchain-core` from 1.2.17 to 1.2.18
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-core==1.2.17...langchain-core==1.2.18)

Updates `numpy` from 2.4.2 to 2.4.3
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/main/doc/RELEASE_WALKTHROUGH.rst)
- [Commits](numpy/numpy@v2.4.2...v2.4.3)

---
updated-dependencies:
- dependency-name: langchain-core
  dependency-version: 1.2.18
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: python-dependencies
- dependency-name: numpy
  dependency-version: 2.4.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: python-dependencies
...

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

Author: dependabot[bot]

lib/rag/layer/requirements.txt

@@ -12,7 +12,7 @@
 # Heavy document processing happens in container: lib/rag/ingestion/ingestion-image/
 
 # Core langchain package for vector store base classes
-langchain-core==1.2.17
+langchain-core==1.2.21
 
 # langchain-community for OpenSearchVectorSearch and PGVector classes
 # This package has many optional dependencies - we only need the core vectorstore functionality
@@ -25,7 +25,7 @@ requests-aws4auth==1.3.1
 
 # Required by langchain-community for vector operations
 # NumPy 2.x has pre-built wheels - pin to specific version to avoid source builds
-numpy==2.4.2
+numpy==2.4.3
 
 # psycopg2-binary provided by Common Layer
 # boto3/botocore provided by Lambda runtime