Improper handling of Python C-API exceptions

Description
===========
The library calls Python APIs (`Logger.log` specifically) without checking whether the Python error indicator was set.

https://github.com/confluentinc/confluent-kafka-python/blob/5a87879681d28375a55203c4839338b13b668046/src/confluent_kafka/src/confluent_kafka.c#L1834

As [Python docs](https://docs.python.org/3/c-api/exceptions.html),
> If the error is not handled or carefully propagated, additional calls into the Python/C API may not behave as intended and may fail in mysterious ways.

Consider a case where `Logger.log` raises an exception, thus, setting the python error indicator. In the next `log_cb` invocation by `librdkafka`, this library would again call `Logger.log` without handling the previous error. Because of this, method calls returns a misleading `SystemError` which is difficult to catch in a python application.

How to reproduce
================
We see this issue consistently when SIGINT is sent to a process which is polling the `Consumer`. `Logger.log` raises a `KeyboardInterrupt` which isn't handled before calling `Logger.log` again. We can't share our proprietary application so here's a minimal reproducer using a mock Logger class to easily reproduce the issue (we see the issue with the default `Logger` class):
```py
from confluent_kafka import Consumer

bootstrap_servers = ""
consumer_config = {
'bootstrap.servers': bootstrap_servers,
'group.id': 'NONE',
'debug': 'all',
}

print("creating consumer")

class Logger:
"""
Mock Logger class to easily reproduce the issue
"""
def log(self, *args, **kwargs):
raise KeyboardInterrupt

logger = Logger()

consumer = Consumer(consumer_config, logger=logger)
print("consumer created")

consumer.subscribe(["some_topic"])

while True:
print("polling")
r = consumer.poll(2)
```

Running this would show this:
```bash
[nix-shell:/codemill/krishan/maestro-api]$ python cf_gh_issue.py |& head -100
creating consumer
consumer created
polling
Traceback (most recent call last):
File "/codemill/krishan/maestro-api/cf_gh_issue.py", line 21, in log
raise KeyboardInterrupt
KeyboardInterrupt

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/codemill/krishan/maestro-api/cf_gh_issue.py", line 21, in log
raise KeyboardInterrupt
SystemError: returned a result with an exception set
```

This `SystemError` is misleading.

Checklist
=========
Please provide the following information:

- [x] confluent-kafka-python and librdkafka version: `2.3.0`
- [x] Apache Kafka broker version: 3.0.0
- [x] Client configuration: `debug=all`
- [x] Operating system: `Red Hat Enterprise Linux 8.9`
- [ ] Provide client logs (with `'debug': '..'` as necessary)
- [ ] Provide broker log excerpts
- [ ] Critical issue