Import router first to avoid circular import issue

tests/base/test_pipelines.py

@@ -2,7 +2,7 @@ from pathlib import Path
 import unittest
 
 from model_server.base.accessors import generate_file_accessor, write_accessor_data_to_file
-from model_server.base.pipelines import segment, segment_zproj
+from model_server.base.pipelines import router, segment, segment_zproj
 
 import model_server.conf.testing as conf
 from tests.base.test_model import DummySemanticSegmentationModel