fix: assign one active engine owner

tests/unit_test.c

@@ -83,6 +83,7 @@ static const struct ct_test tests[] = {
 	{ "engine/selects-visible-candidate", engine_selects_visible_candidate },
 	{ "engine/candidate-shortcut-modifiers", engine_candidate_shortcut_modifiers },
 	{ "engine/dictionary-queue-latest", engine_dictionary_queue_latest_wins },
+	{ "engine/active-owner-lifecycle", engine_active_owner_lifecycle },
 	{ "engine/commit-contract", engine_commit_contract },
 	{ "engine/language-switch-state", engine_language_switch_state },
 	{ "engine/telex-history-bound", engine_telex_history_bound },