Fix flake8

Author: cecille

src/controller/python/chip/ChipDeviceCtrl.py

@@ -51,7 +51,7 @@
 from .clusters import ClusterObjects as ClusterObjects
 from .clusters import Command as ClusterCommand
 from .clusters import Objects as GeneratedObjects
-from .clusters.Attribute import AttributeCache, AttributePath
+from .clusters.Attribute import AttributeCache, AttributePath, ValueDecodeFailure
 from .clusters.CHIPClusters import ChipClusters
 from .crypto import p256keypair
 from .exceptions import UnknownAttribute, UnknownCommand

src/python_testing/basic_composition_support.py

@@ -28,7 +28,7 @@
 import chip.clusters.ClusterObjects
 import chip.tlv
 from chip.ChipDeviceCtrl import TLVJsonConverter
-from chip.clusters.Attribute import AttributeCache, AttributePath, ValueDecodeFailure
+from chip.clusters.Attribute import ValueDecodeFailure
 from mobly import asserts