Native页面回传数据到flutter页面bug

v3.0-beta.10 当Flutter页面 A 使用withContainer：true 打开Flutter页面B后，FlutterB的uniqueId会从时间戳转变为16进制字符串，但是在FlutterBoostAppState _pendingResult缓存的FlutterB使用的key是时间戳的uniqueId，导致在打开一个新的Native界面之后onNativeResult时候找不到真正的FlutterB页面来接收返回数据

Start in FlutterBoostAppState and trace how _pendingResult keys are created and later matched during onNativeResult. Reproduce the withContainer scenario where Flutter page B's uniqueId changes from a timestamp to a hexadecimal string; done means native return data reaches the correct FlutterB page after opening another native screen.

Written by the indexing model from the issue text.