pool: Handle non-shard-aware endpoints in logging

When connecting to non-shard-aware endpoints, conn.features.shard_id is None.
Previously, this would cause a TypeError when logging with %i format specifier.

```
  Traceback (most recent call last):
    File "/usr/lib64/python3.12/logging/__init__.py", line 1160, in emit
      msg = self.format(record)
            ^^^^^^^^^^^^^^^^^^^
    File "/usr/lib64/python3.12/logging/__init__.py", line 999, in format
      return fmt.format(record)
             ^^^^^^^^^^^^^^^^^^
    File "/usr/lib/python3.12/site-packages/_pytest/logging.py", line 136, in format
      return super().format(record)
             ^^^^^^^^^^^^^^^^^^^^^^
    File "/usr/lib64/python3.12/logging/__init__.py", line 703, in format
      record.message = record.getMessage()
                       ^^^^^^^^^^^^^^^^^^^
    File "/usr/lib64/python3.12/logging/__init__.py", line 392, in getMessage
      msg = msg % self.args
            ~~~~^~~~~~~~~~~
  TypeError: %i format: a real number is required, not NoneType
  Call stack:
    File "/usr/lib64/python3.12/threading.py", line 1032, in _bootstrap
      self._bootstrap_inner()
    File "/usr/lib64/python3.12/threading.py", line 1075, in _bootstrap_inner
      self.run()
    File "/usr/lib64/python3.12/threading.py", line 1012, in run
      self._target(*self._args, **self._kwargs)
    File "/usr/lib64/python3.12/concurrent/futures/thread.py", line 92, in _worker
      work_item.run()
    File "/usr/lib64/python3.12/concurrent/futures/thread.py", line 58, in run
      result = self.fn(*self.args, **self.kwargs)
  Message: 'Received a connection %s for shard_id=%i on host %s'
  Arguments: (140333813254336, None, <Host: 127.67.173.34:9042 dc2>)
```

Now prints -1 as a fallback value instead of raising an exception.

This fixes logging failures that occurred when:
- Connecting to non-shard-aware endpoints
- Debug logging level was enabled

Signed-off-by: Kefu Chai <[email protected]>

Author: tchaikov

cassandra/pool.py

@@ -731,7 +731,11 @@ def _open_connection_to_missing_shard(self, shard_id):
         else:
             conn = self._session.cluster.connection_factory(self.host.endpoint, host_conn=self, on_orphaned_stream_released=self.on_orphaned_stream_released)
 
-        log.debug("Received a connection %s for shard_id=%i on host %s", id(conn), conn.features.shard_id, self.host)
+        log.debug(
+            "Received a connection %s for shard_id=%i on host %s",
+            id(conn),
+            conn.features.shard_id if conn.features.shard_id is not None else -1,
+            self.host)
         if self.is_shutdown:
             log.debug("Pool for host %s is in shutdown, closing the new connection (%s)", self.host, id(conn))
             conn.close()