Add KeepAliveClientRequest class for k8s async client

[kevingrismore]

Closes #14954

Swaps the request class on the async k8s base client for one that has TCP keepalive enabled after the client is built. Refer to aio-libs/aiohttp#3904 (comment)

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[kevingrismore]

To be clear about why I opened this, client.rest_client.pool_manager.connection_pool_kw in the previous implementation is accessing a property of a urllib3 connection pool. aiohttp has a different object structure and we need to handle the keepalive configuration slightly differently.

[zzstoatzz]

🧼

[kevingrismore]

Before: crash with error matching reports when run in a cluster with a 4 minute TCP load balancing timeout rule

Error occurred while streaming logs - Job will continue to run but logs will no longer be streamed to stdout.
Traceback (most recent call last):
  File "/usr/local/lib/python3.11/site-packages/aiohttp/client_proto.py", line 94, in connection_lost
    uncompleted = self._parser.feed_eof()
                  ^^^^^^^^^^^^^^^^^^^^^^^
  File "aiohttp/_http_parser.pyx", line 513, in aiohttp._http_parser.HttpParser.feed_eof
aiohttp.http_exceptions.TransferEncodingError: 400, message:
  Not enough data for satisfy transfer length header.

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

Traceback (most recent call last):
  File "/usr/local/lib/python3.11/site-packages/prefect_kubernetes/worker.py", line 939, in _stream_job_logs
    async for line in logs.content:
  File "/usr/local/lib/python3.11/site-packages/aiohttp/streams.py", line 50, in __anext__
    rv = await self.read_func()
         ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/aiohttp/streams.py", line 317, in readline
    return await self.readuntil()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/aiohttp/streams.py", line 351, in readuntil
    await self._wait("readuntil")
  File "/usr/local/lib/python3.11/site-packages/aiohttp/streams.py", line 312, in _wait
    await waiter
aiohttp.client_exceptions.ClientPayloadError: Response payload is not completed: <TransferEncodingError: 400, message='Not enough data for satisfy transfer length header.'>. ConnectionResetError(104, 'Connection reset by peer')

After: no crash, flow completes successfully