fix(Picker): The get parameter method should be placed in the correct…

[front-refined]

// wait nextTick to ensure the model value is update to date
// when confirm event is emitted

如注释描述，需要在 nextTick 后去获取最新的值，所以要放在 nextTick 的回调里获取最新。
这块需要手动测试，在配置了 min-date 后，滚动还没有停止时，就快速直接点击 confirm 按钮的场景。

#11878

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.75%. Comparing base (ec5b45b) to head (1ced19e).
Report is 48 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13381      +/-   ##
==========================================
+ Coverage   89.60%   89.75%   +0.15%     
==========================================
  Files         257      257              
  Lines        7013     7021       +8     
  Branches     1736     1737       +1     
==========================================
+ Hits         6284     6302      +18     
+ Misses        384      378       -6     
+ Partials      345      341       -4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[inottn]

Could you please add a test for the case? Thanks.

[front-refined]

Could you please add a test for the case? Thanks.

hello，你可以看下我的 github 仓库 https://github.com/front-refined/vant-picker-issue 描述、视频和运行起来调试，这个 bug 存在偶发性，感谢

[inottn]

你好，我对于这个 bug 的修复没有疑义，只是为了避免之后该 bug 的回归，我们最好有一个对应的单元测试。

[front-refined]

你好，我对于这个bug的修复没有疑义，只是为了避免之后该bug的回归，我们最好有一个对应的单元测试。

你好，感谢答复，我尝试补充了单元测试，你看 ok 吗

[front-refined]

@inottn 你好，帮忙 review 下

[mouse-007]

这里的confirm的返回值与事件confirm输出的值不一致