CameraITS: remove cv2 dependcy from image.py

So that only tests require opencv needs to import opencv

Test: python tools/run_all_tests.py scenes=0,3 ...
Bug: 31995717
Change-Id: I08ff1ddd8b0508220180e8c1188c48adba66f26d
diff --git a/apps/CameraITS/tests/scene3/test_lens_position.py b/apps/CameraITS/tests/scene3/test_lens_position.py
index e2bd040..f850e3d 100644
--- a/apps/CameraITS/tests/scene3/test_lens_position.py
+++ b/apps/CameraITS/tests/scene3/test_lens_position.py
@@ -15,6 +15,7 @@
 import os
 
 import its.caps
+import its.cv2image
 import its.device
 import its.image
 import its.objects
@@ -58,9 +59,9 @@
     """
 
     # initialize chart class
-    chart = its.image.Chart(CHART_FILE, CHART_HEIGHT, CHART_DISTANCE,
-                            CHART_SCALE_START, CHART_SCALE_STOP,
-                            CHART_SCALE_STEP)
+    chart = its.cv2image.Chart(CHART_FILE, CHART_HEIGHT, CHART_DISTANCE,
+                                CHART_SCALE_START, CHART_SCALE_STOP,
+                                CHART_SCALE_STEP)
 
     # find chart location
     xnorm, ynorm, wnorm, hnorm = chart.locate(cam, props, fmt, sensitivity,