[NNCF] Missing import statements in utils.py

Changes:

1. Added missing import statements in nncf/common/graph/utils.py

Reason for changes:

(openvinotoolkit#3249) Torch and Tensorflow backend-specific methods need to be removed
from common layer attributes and all related calls need to be replaced
by their corresponding legacy function calls

Author: shumaari

nncf/common/graph/utils.py

@@ -14,6 +14,11 @@
 
 from nncf.common.graph import NNCFGraph
 from nncf.common.graph import NNCFNode
+from nncf.common.graph.layer_attributes import WeightedLayerAttributes
+from nncf.common.graph.layer_attributes import GenericWeightedLayerAttributes
+from nncf.common.graph.layer_attributes import LinearLayerAttributes
+from nncf.common.graph.layer_attributes import ConvolutionLayerAttributes
+from nncf.common.graph.layer_attributes import GroupNormLayerAttributes
 from nncf.common.graph.operator_metatypes import OperatorMetatype
 from nncf.common.logging import nncf_logger
 from nncf.common.pruning.utils import traverse_function