Samples: Fix auto2d tuning for variable aperture camera

Fix Auto2D tuning logic to skip aperture changes only for
fixed‑aperture cameras (e.g., Zivid 3), instead of assuming
aperture changes for all cameras.

Author: csu-bot-zivid

source/applications/advanced/auto_2d_settings.py

@@ -406,7 +406,7 @@ def _adjust_acquisition_settings_2d(
         Updated tuning index
 
     """
-    if fnum_limits[1] != fnum_limits[0]:
+    if (fnum_limits[1] == fnum_limits[0]) and (tuning_index == 1):
         tuning_index = 2
 
     if tuning_index == 1: