🧹 Remove unused json import in test_calibration.py

Co-authored-by: manupawickramasinghe <73810867+manupawickramasinghe@users.noreply.github.com>

Author: google-labs-jules[bot]

aether-arena/calibration/test_calibration.py

@@ -6,7 +6,6 @@
 
 Run:  python test_calibration.py    (or via pytest)
 """
-import json
 import subprocess
 import sys
 import tempfile