community[patch]: Adding HEADER to the list of supported locations (#21946)

**Description:** adds headers to the list of supported locations when
generating the openai function schema

libs/community/tests/unit_tests/utilities/test_openapi.py

@@ -0,0 +1,44 @@
+from pathlib import Path
+
+import pytest
+from langchain.chains.openai_functions.openapi import openapi_spec_to_openai_fn
+
+from langchain_community.utilities.openapi import (  # noqa: E402 # ignore: community-import
+    OpenAPISpec,
+)
+
+EXPECTED_OPENAI_FUNCTIONS_HEADER_PARAM = [
+    {
+        "name": "showPetById",
+        "description": "Info for a specific pet",
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "headers": {
+                    "type": "object",
+                    "properties": {
+                        "header_param": {
+                            "type": "string",
+                            "description": "A header param",
+                        }
+                    },
+                    "required": ["header_param"],
+                }
+            },
+        },
+    }
+]
+
+
+@pytest.mark.requires("openapi_pydantic")
+def test_header_param() -> None:
+    spec = OpenAPISpec.from_file(
+        Path(__file__).parent.parent
+        / "data"
+        / "openapi_specs"
+        / "openapi_spec_header_param.json",
+    )
+
+    openai_functions, _ = openapi_spec_to_openai_fn(spec)
+
+    assert openai_functions == EXPECTED_OPENAI_FUNCTIONS_HEADER_PARAM