core[patch]: export tool output parsers from langchain_core.output_parsers (#23305)

These currently read off AIMessage.tool_calls, and only fall back to
OpenAI parsing if tool calls aren't populated.

Importing these from `openai_tools` (e.g., in our [tool calling
docs](https://python.langchain.com/v0.2/docs/how_to/tool_calling/#tool-calls))
can lead to confusion.

After landing, would need to release core and update docs.

libs/core/tests/unit_tests/output_parsers/test_imports.py

@@ -15,6 +15,9 @@ EXPECTED_ALL = [
     "XMLOutputParser",
     "JsonOutputParser",
     "PydanticOutputParser",
+    "JsonOutputToolsParser",
+    "JsonOutputKeyToolsParser",
+    "PydanticToolsParser",
 ]