build: bump the langchain group across 1 directory with 2 updates

Bumps the langchain group with 2 updates in the / directory: [langchain](https://github.com/langchain-ai/langchain) and [langchain-community](https://github.com/langchain-ai/langchain).


Updates `langchain` from 0.2.12 to 0.2.16
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain==0.2.12...langchain==0.2.16)

Updates `langchain-community` from 0.2.11 to 0.2.16
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-community==0.2.11...langchain-community==0.2.16)

---
updated-dependencies:
- dependency-name: langchain
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: langchain
- dependency-name: langchain-community
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: langchain
...

Signed-off-by: dependabot[bot] <[email protected]>

pyproject.toml

@@ -18,8 +18,8 @@ azure-storage-blob = "12.20.0"
 azure-identity = "1.17.1"
 flask = {extras = ["async"], version = "^3.0.3"}
 openai = "1.38.0"
-langchain = "0.2.12"
-langchain-community = "0.2.11"
+langchain = "0.2.16"
+langchain-community = "0.2.16"
 langchain-openai = "0.1.20"
 requests = "2.32.3"
 tiktoken = "0.7.0"