test(settings): add allow_public_custom_components to composition field list

The public-flow trusted-code fix added the allow_public_custom_components
setting to SecuritySettings, which bumped Settings.model_fields to 147 and
tripped test_field_count_unchanged (147 != 146). Add the field to the
curated EXPECTED_FIELDS set under a 1.10.1 section.

Author: erichare

src/lfx/tests/unit/services/settings/test_settings_composition.py

@@ -195,6 +195,9 @@
     "telemetry_writer_size_strategy",
     "telemetry_writer_batch_size_bytes",
     "telemetry_writer_max_queue_bytes",
+    # ---- Added in 1.10.1 ----
+    # SecuritySettings
+    "allow_public_custom_components",
 }