This PR formats all the `*.py` files found under the `tests/integration`
folder. It also reorders the imports and cleans up a bunch of unused
imports.
The formatting also takes care of other things like wrapping lines and
fixing spaces and indents such that the tests look more readable.
This adds integration tests to test the asynchronous_metric_log table
for event_time_microseconds field.
Asynchronous metrics are updated once every 60s, so this setting needs
to be overridden for having those metrics available in time so that the
tests can run. So the `asynchronous_metric_update_period_s` setting is
being overriden to be 2s.