Potential fix for flaky ion_cyclotron_source test.

This removes the default whitespaces from the seperators which will hopefully fix the flaky read.

PiperOrigin-RevId: 711712482

torax/sources/tests/ion_cyclotron_source.py

@@ -91,7 +91,7 @@ def setUpClass(cls):
     )
     # pylint: enable=protected-access
     with open(_DUMMY_MODEL_PATH, "w") as f:
-      json.dump(model_config, f)
+      json.dump(model_config, f, indent=4, separators=(",", ":"))
     cls.dummy_input = model_input
     cls.dummy_output = model_output
     super().setUpClass(