Ignore unused import error

These imports are used to break circular imports in a very convoluted
set of circular dependencies. To do that some types need to be specified
as strings and use `typing.TYPE_CHECKING` to conditionally add imports,
and it seems like flake8 doesn't detect those strings as types being
used.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/sdk/microgrid/_data_pipeline.py

@@ -33,7 +33,7 @@
         DataSourcingActor,
         ResamplerConfig,
     )
-    from ..actor.power_distributing import (
+    from ..actor.power_distributing import (  # noqa: F401 (imports used by string type hints)
         BatteryStatus,
         PowerDistributingActor,
         Request,