Wait expert: Test `test_dummy` fails frequently

Has been a problem in the Build Service tests already, now also in GH Actions Python 3.6 full:

======================================================================
FAIL: test_dummy (intelmq.tests.bots.experts.wait.test_expert.TestWaitExpertBot)
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Traceback (most recent call last):
  File "/home/runner/work/intelmq/intelmq/intelmq/tests/bots/experts/wait/test_expert.py", line 35, in test_dummy
    self.assertLess(after-before, 0.5)
AssertionError: 0.673896074295044 not less than 0.5
-------------------- >> begin captured logging << --------------------
test-bot: INFO: WaitExpertBot initialized with id test-bot and intelmq 3.0.0.rc.1 and python 3.6.13 (default, Feb 16 2021, 11:53:02) as process 4289.
test-bot: DEBUG: Library path: '/home/runner/work/intelmq/intelmq/intelmq/lib/bot.py'.
test-bot: DEBUG: Defaults configuration: parameter 'destination_pipeline_broker' loaded with value 'pythonlist'.
test-bot: DEBUG: Defaults configuration: parameter 'logging_handler' loaded with value 'stream'.
test-bot: DEBUG: Defaults configuration: parameter 'logging_path' loaded with value None.
test-bot: DEBUG: Defaults configuration: parameter 'logging_level' loaded with value 'DEBUG'.
test-bot: DEBUG: Defaults configuration: parameter 'rate_limit' loaded with value 0.
test-bot: DEBUG: Defaults configuration: parameter 'retry_delay' loaded with value 0.
test-bot: DEBUG: Defaults configuration: parameter 'error_retry_delay' loaded with value 0.
test-bot: DEBUG: Defaults configuration: parameter 'error_max_retries' loaded with value 0.
test-bot: DEBUG: Defaults configuration: parameter 'redis_cache_host' loaded with value 'localhost'.
test-bot: DEBUG: Defaults configuration: parameter 'redis_cache_port' loaded with value 6379.
test-bot: DEBUG: Defaults configuration: parameter 'redis_cache_db' loaded with value 4.
test-bot: DEBUG: Defaults configuration: parameter 'redis_cache_ttl' loaded with value 10.
test-bot: DEBUG: Defaults configuration: parameter 'redis_cache_password' loaded with value 'HIDDEN'.
test-bot: DEBUG: Defaults configuration: parameter 'source_pipeline_broker' loaded with value 'pythonlist'.
test-bot: DEBUG: Defaults configuration: parameter 'testing' loaded with value True.
test-bot: INFO: Bot is starting.
test-bot: DEBUG: Loading runtime configuration from '/opt/intelmq/etc/runtime.yaml'.
test-bot: DEBUG: Runtime configuration: parameter 'destination_pipeline_broker' loaded with value 'pythonlist'.
test-bot: DEBUG: Runtime configuration: parameter 'logging_handler' loaded with value 'stream'.
test-bot: DEBUG: Runtime configuration: parameter 'logging_path' loaded with value None.
test-bot: DEBUG: Runtime configuration: parameter 'logging_level' loaded with value 'DEBUG'.
test-bot: DEBUG: Runtime configuration: parameter 'rate_limit' loaded with value 0.
test-bot: DEBUG: Runtime configuration: parameter 'retry_delay' loaded with value 0.
test-bot: DEBUG: Runtime configuration: parameter 'error_retry_delay' loaded with value 0.
test-bot: DEBUG: Runtime configuration: parameter 'error_max_retries' loaded with value 0.
test-bot: DEBUG: Runtime configuration: parameter 'redis_cache_host' loaded with value 'localhost'.
test-bot: DEBUG: Runtime configuration: parameter 'redis_cache_port' loaded with value 6379.
test-bot: DEBUG: Runtime configuration: parameter 'redis_cache_db' loaded with value 4.
test-bot: DEBUG: Runtime configuration: parameter 'redis_cache_ttl' loaded with value 10.
test-bot: DEBUG: Runtime configuration: parameter 'redis_cache_password' loaded with value 'HIDDEN'.
test-bot: DEBUG: Runtime configuration: parameter 'source_pipeline_broker' loaded with value 'pythonlist'.
test-bot: DEBUG: Runtime configuration: parameter 'testing' loaded with value True.
test-bot: DEBUG: Runtime configuration: parameter 'destination_queues' loaded with value {'_default': 'test-bot-output'}.
test-bot: DEBUG: Environment configuration: parameter 'test_exotic' loaded with value 1.
test-bot: DEBUG: Environment configuration: parameter 'test_databases' loaded with value 1.
test-bot: DEBUG: Loading Harmonization configuration from '/opt/intelmq/etc/harmonization.conf'.
test-bot: DEBUG: Loading source pipeline and queue 'test-bot-queue'.
test-bot: DEBUG: Connected to source queue.
test-bot: DEBUG: Loading destination pipeline and queues {'_default': 'test-bot-output'}.
test-bot: DEBUG: Connected to destination queues.
test-bot: DEBUG: Wait mode is dummy.
test-bot: INFO: Bot initialization completed.
test-bot: DEBUG: Waiting for incoming message.
test-bot: DEBUG: Received message {'time.observation': '2015-01-01T00:00:00+00:00'}.
test-bot: DEBUG: Sending message to path '_default'.
test-bot: DEBUG: Testing environment detected, returning now.
test-bot: INFO: Processed 1 messages since last logging.
test-bot: DEBUG: Disconnected from source pipeline.
test-bot: DEBUG: Disconnected from destination pipeline.
test-bot: INFO: Bot stopped.
--------------------- >> end captured logging << ---------------------

Maybe better check the logging line instead of the timing? Ignore on GH Actions as well?