chore: add traceback info to the failed to send message [backport 3.10] (#14353)

## Checklist
- [X] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Signed-off-by: Juanjo Alvarez <[email protected]>

Author: juanjux

ddtrace/internal/writer/writer.py

@@ -406,6 +406,7 @@ def _flush_queue_with_client(self, client: WriterClientBase, raise_exc: bool = F
                     n_traces,
                     self._intake_endpoint(client),
                     self.RETRY_ATTEMPTS,
+                    exc_info=True,
                 )
         finally:
             self._metrics_dist("http.sent.bytes", len(encoded))

tests/integration/test_integration.py

@@ -109,6 +109,7 @@ def test_uds_wrong_socket_path():
             1,
             "unix:///tmp/ddagent/nosockethere/{}/traces".format(encoding if encoding else "v0.5"),
             3,
+            exc_info=True,
         )
     ]
     log.error.assert_has_calls(calls)
@@ -356,6 +357,7 @@ def test_trace_generates_error_logs_when_trace_agent_url_invalid():
             1,
             "http://localhost:8125/{}/traces".format(encoding if encoding else "v0.5"),
             3,
+            exc_info=True,
         )
     ]
     log.error.assert_has_calls(calls)