CI failure: ConnectionRateLimitTest.connection_rate_test times out reading data

[andrwng]

FAIL test: ConnectionRateLimitTest.connection_rate_test (1/24 runs)
  failure at 2022-08-17T07:38:31.224Z: TimeoutError('')
      in job https://buildkite.com/redpanda/vtools/builds/3271#0182a9c3-a7aa-4850-a6b7-65bee8152d80

Stack trace:

====================================================================================================
test_id:    rptest.tests.connection_rate_limit_test.ConnectionRateLimitTest.connection_rate_test
status:     FAIL
run time:   5 minutes 37.287 seconds


    TimeoutError('')
Traceback (most recent call last):
  File "/home/ubuntu/.local/lib/python3.10/site-packages/ducktape/tests/runner_client.py", line 135, in run
    data = self.run_test()
  File "/home/ubuntu/.local/lib/python3.10/site-packages/ducktape/tests/runner_client.py", line 227, in run_test
    return self.test_context.function(self.test)
  File "/home/ubuntu/redpanda/tests/rptest/tests/connection_rate_limit_test.py", line 123, in connection_rate_test
    time2 = self.get_read_time(self.RANDOM_READ_PARALLEL * 2)
  File "/home/ubuntu/redpanda/tests/rptest/tests/connection_rate_limit_test.py", line 109, in get_read_time
    connection_time = self.read_data(consumers_count)
  File "/home/ubuntu/redpanda/tests/rptest/tests/connection_rate_limit_test.py", line 94, in read_data
    wait_until(consumed,
  File "/home/ubuntu/.local/lib/python3.10/site-packages/ducktape/utils/util.py", line 58, in wait_until
    raise TimeoutError(err_msg() if callable(err_msg) else err_msg) from last_exception
ducktape.errors.TimeoutError

[bharathv]

Another instance: https://ci-artifacts.dev.vectorized.cloud/vtools/0182c381-f5d0-413b-a501-4d7eae01ff51/vbuild/ducktape/results/2022-08-22--001/ConnectionRateLimitTest/connection_rate_test/93/