refactor: import is_test_mode from autoconf (canonical source)

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

Author: 2 people

autogalaxy/quantity/model/visualizer.py

@@ -1,7 +1,7 @@
 import os
 
 import autofit as af
-from autofit.non_linear.test_mode import is_test_mode
+from autoconf.test_mode import is_test_mode
 
 from autogalaxy.quantity.model.plotter import PlotterQuantity