ITS: test_num_faces.py --> always run do_3a()

Other changes:
  fix pylint error for import order

bug: 237052727
Change-Id: I8c59a078ce0886cb5230ca6b90de0ca49fa8ee93
diff --git a/apps/CameraITS/tests/scene2_a/test_num_faces.py b/apps/CameraITS/tests/scene2_a/test_num_faces.py
index 304b67b3..f7e111b 100644
--- a/apps/CameraITS/tests/scene2_a/test_num_faces.py
+++ b/apps/CameraITS/tests/scene2_a/test_num_faces.py
@@ -16,6 +16,8 @@
 
 import logging
 import os.path
+
+import cv2
 from mobly import test_runner
 
 import its_base_test
@@ -23,7 +25,6 @@
 import capture_request_utils
 import image_processing_utils
 import its_session_utils
-import cv2
 
 FD_MODE_OFF = 0
 FD_MODE_SIMPLE = 1
@@ -149,8 +150,7 @@
       logging.debug('active array size: %s', str(a))
       file_name_stem = os.path.join(self.log_path, NAME)
 
-      if camera_properties_utils.read_3a(props):
-        _, _, _, _, _ = cam.do_3a(get_results=True, mono_camera=mono_camera)
+      cam.do_3a(mono_camera=mono_camera)
 
       for fd_mode in fd_modes:
         logging.debug('face detection mode: %d', fd_mode)