test: remove undo tests for non-clip operations

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>

test_tui.c

@@ -1646,9 +1646,6 @@ int main(void) {
     test_undo_clip_state_cycle();
     test_undo_clears_redo_on_new_action();
     test_undo_reset_clip();
-    test_undo_quantize_change();
-    test_undo_threshold_change();
-    test_undo_transport_reset();
     test_undo_paste();
     
     printf("\nAll TUI tests passed!\n");