pytest_plugin: Increase poll timeout in consume_messages

This prevents flaky test_storage_replayer in swh-storage tests.

swh/journal/pytest_plugin.py

@@ -51,7 +51,7 @@ def consume_messages(consumer, kafka_prefix, expected_messages):
                 f"Only {fetched_messages}/{expected_messages} fetched"
             )
 
-        msg = consumer.poll(timeout=0.01)
+        msg = consumer.poll(timeout=0.1)
 
         if not msg:
             retries_left -= 1