community: move to separate repo (#31060)

langchain-community is moving to
https://github.com/langchain-ai/langchain-community

.github/scripts/prep_api_docs_build.py

@@ -20,6 +20,8 @@ def get_target_dir(package_name: str) -> Path:
     base_path = Path("langchain/libs")
     if package_name_short == "experimental":
         return base_path / "experimental"
+    if package_name_short == "community":
+        return base_path / "community"
     return base_path / "partners" / package_name_short