community: fix tool appending logic and update planner prompt in OpenAPI agent toolkit (#24384)

**Description:**
- Updated the format for the 'Action' section in the planner prompt to
ensure it must be one of the tools without additional words. Adjusted
the phrasing from "should be" to "must be" for clarity and
enforceability.
- Corrected the tool appending logic in the
`_create_api_controller_agent` function to ensure that
`RequestsDeleteToolWithParsing` and `RequestsPatchToolWithParsing` are
properly added to the tools list for "DELETE" and "PATCH" operations.

**Issue:** #24382

**Dependencies:** None

**Twitter handle:** @lunara_x

---------

Co-authored-by: Chester Curme <chester.curme@gmail.com>

libs/community/langchain_community/agent_toolkits/openapi/planner.py

@@ -292,17 +292,21 @@ def _create_api_controller_agent(
         )
     if "DELETE" in allowed_operations:
         delete_llm_chain = LLMChain(llm=llm, prompt=PARSING_DELETE_PROMPT)
-        RequestsDeleteToolWithParsing(  # type: ignore[call-arg]
-            requests_wrapper=requests_wrapper,
-            llm_chain=delete_llm_chain,
-            allow_dangerous_requests=allow_dangerous_requests,
+        tools.append(
+            RequestsDeleteToolWithParsing(  # type: ignore[call-arg]
+                requests_wrapper=requests_wrapper,
+                llm_chain=delete_llm_chain,
+                allow_dangerous_requests=allow_dangerous_requests,
+            )
         )
     if "PATCH" in allowed_operations:
         patch_llm_chain = LLMChain(llm=llm, prompt=PARSING_PATCH_PROMPT)
-        RequestsPatchToolWithParsing(  # type: ignore[call-arg]
-            requests_wrapper=requests_wrapper,
-            llm_chain=patch_llm_chain,
-            allow_dangerous_requests=allow_dangerous_requests,
+        tools.append(
+            RequestsPatchToolWithParsing(  # type: ignore[call-arg]
+                requests_wrapper=requests_wrapper,
+                llm_chain=patch_llm_chain,
+                allow_dangerous_requests=allow_dangerous_requests,
+            )
         )
     if not tools:
         raise ValueError("Tools not found")