fix: call _on_llm_error() (#13581)

Description: There's a copy-paste typo where on_llm_error() calls
_on_chain_error() instead of _on_llm_error().
Issue: #13580 
Dependencies: None
Tag maintainer: @hwchase17 
Twitter handle: @jwatte

"Run `make format`, `make lint` and `make test` to check this locally."
The test scripts don't work in a plain Ubuntu LTS 20.04 system.
It looks like the dev container pulling is stuck. Or maybe the internet
is just ornery today.

---------

Co-authored-by: jwatte <jwatte@observeinc.com>
Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

libs/core/langchain_core/tracers/base.py

@@ -224,7 +224,7 @@ class BaseTracer(BaseCallbackHandler, ABC):
         llm_run.end_time = datetime.utcnow()
         llm_run.events.append({"name": "error", "time": llm_run.end_time})
         self._end_trace(llm_run)
-        self._on_chain_error(llm_run)
+        self._on_llm_error(llm_run)
         return llm_run
 
     def on_chain_start(

libs/langchain/tests/unit_tests/callbacks/tracers/test_base_tracer.py

@@ -332,6 +332,42 @@ def test_tracer_llm_run_on_error() -> None:
     assert tracer.runs == [compare_run]
 
 
+@freeze_time("2023-01-01")
+def test_tracer_llm_run_on_error_callback() -> None:
+    """Test tracer on an LLM run with an error and a callback."""
+    exception = Exception("test")
+    uuid = uuid4()
+
+    compare_run = Run(
+        id=str(uuid),
+        start_time=datetime.utcnow(),
+        end_time=datetime.utcnow(),
+        events=[
+            {"name": "start", "time": datetime.utcnow()},
+            {"name": "error", "time": datetime.utcnow()},
+        ],
+        extra={},
+        execution_order=1,
+        child_execution_order=1,
+        serialized=SERIALIZED,
+        inputs=dict(prompts=[]),
+        outputs=None,
+        error=repr(exception),
+        run_type="llm",
+    )
+
+    class FakeTracerWithLlmErrorCallback(FakeTracer):
+        error_run = None
+
+        def _on_llm_error(self, run: Run) -> None:
+            self.error_run = run
+
+    tracer = FakeTracerWithLlmErrorCallback()
+    tracer.on_llm_start(serialized=SERIALIZED, prompts=[], run_id=uuid)
+    tracer.on_llm_error(exception, run_id=uuid)
+    assert tracer.error_run == compare_run
+
+
 @freeze_time("2023-01-01")
 def test_tracer_chain_run_on_error() -> None:
     """Test tracer on a Chain run with an error."""