langchain: Fix for issue #14631 - .devcontainer doesnt build (#15251)

- **Description:** Fix for issue #14631
- **Issue:** This fixes [Issue
#14631](https://github.com/langchain-ai/langchain/issues/14631)
- **Twitter handle:** [@consultchrisq
](https://twitter.com/consultchrisq?lang=en)

libs/langchain/dev.Dockerfile

@@ -40,5 +40,11 @@ COPY libs/langchain/pyproject.toml libs/langchain/poetry.toml ./
 # Copy the langchain library for installation
 COPY libs/langchain/ libs/langchain/
 
+# Copy the core library for installation
+COPY libs/core ../core
+
+# Copy the community library for installation
+COPY libs/community/ ../community/
+
 # Install the Poetry dependencies (this layer will be cached as long as the dependencies don't change)
-RUN poetry install --no-interaction --no-ansi --with dev,test,docs
+RUN poetry install --no-interaction --no-ansi --with dev,test,docs