disposeFloating method
释放 key 对应的 FloatingOverlay
Implementation
void disposeFloating(Object key) {
// remove from cache first so containsFloating reflects removal immediately
var floating = _floatingCache.remove(key);
if (floating == null) return;
try {
floating.close();
} catch (_) {
// ignore
}
try {
floating.dispose();
} catch (_) {
// ignore
}
}