ddtrace.patch breaks serializing loguru logger

Summary of problem

Patching loguru logger in serializing mode breaks it when certain named arguments (for example file) are passed to log entry.

Which version of dd-trace-py are you using?

ddtrace 2.8.0

Which version of pip are you using?

pip 24.0

Which libraries and their versions are you using?

`pip freeze`

``` attrs==23.2.0 bytecode==0.15.1 cattrs==23.2.3 ddsketch==3.0.1 ddtrace==2.8.0 Deprecated==1.2.14 envier==0.5.1 importlib-metadata==7.0.0 loguru==0.7.2 opentelemetry-api==1.24.0 protobuf==5.26.1 setuptools==69.2.0 six==1.16.0 sqlparse==0.4.4 typing_extensions==4.11.0 wrapt==1.16.0 xmltodict==0.13.0 zipp==3.18.1 ```

How can we reproduce your problem?

from os import environ
environ['LOGURU_SERIALIZE'] = '1'

import ddtrace
import loguru

ddtrace.patch(loguru=True)

loguru.logger.error("Message with file attribute: {file}", file="example")

What is the result that you get?

--- Logging error in Loguru Handler #0 ---
Record was: {'elapsed': datetime.timedelta(microseconds=11578), 'exception': None, 'extra': {'file': 'example', 'dd.trace_id': '0', 'dd.span_id': '0', 'dd.env': '', 'dd.service': '', 'dd.version': ''}, 'file': 'example', 'function': '<module>', 'level': (name='ERROR', no=40, icon='❌'), 'line': 9, 'message': 'Message with file attribute: example', 'module': 'ddbug', 'name': '__main__', 'process': (id=79946, name='MainProcess'), 'thread': (id=8214018752, name='MainThread'), 'time': datetime(2024, 4, 10, 15, 39, 12, 448643, tzinfo=datetime.timezone(datetime.timedelta(days=-1, seconds=61200), 'PDT')), 'dd.trace_id': '0', 'dd.span_id': '0', 'dd.env': '', 'dd.service': '', 'dd.version': ''}
Traceback (most recent call last):
  File "venv/lib/python3.12/site-packages/loguru/_handler.py", line 195, in emit
    formatted = self._serialize_record(formatted, record)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "venv/lib/python3.12/site-packages/loguru/_handler.py", line 271, in _serialize_record
    "file": {"name": record["file"].name, "path": record["file"].path},
                     ^^^^^^^^^^^^^^^^^^^
AttributeError: 'str' object has no attribute 'name'
--- End of logging error ---

What is the result that you expected?

{"text": "2024-04-10 15:39:28.534 | ERROR    | __main__:<module>:9 - Message with file attribute: example\n", "record": {"elapsed": {"repr": "0:00:00.002795", "seconds": 0.002795}, "exception": null, "extra": {"file": "example"}, "file": {"name": "ddbug.py", "path": "ddbug.py"}, "function": "<module>", "level": {"icon": "❌", "name": "ERROR", "no": 40}, "line": 9, "message": "Message with file attribute: example", "module": "ddbug", "name": "__main__", "process": {"id": 79970, "name": "MainProcess"}, "thread": {"id": 8214018752, "name": "MainThread"}, "time": {"repr": "2024-04-10 15:39:28.534128-07:00", "timestamp": 1712788768.534128}}}

DataDog / dd-trace-py

ddtrace.patch breaks serializing loguru logger #8939