[Bug Report] dialog和tooltip层级问题

[horizon188]

Element UI version

2.15.14

OS/Browsers version

window，chrome131.0.6778.71

Vue version

2.6.10

Reproduction Link

https://element.eleme.cn/#/zh-CN/component/dialog

Steps to reproduce

提示框打开次数小于弹框打开次数就会出现提示框的z-index大于弹框的z-index，出现提示框被弹框遮挡的问题

What is Expected?

提示框总是在弹框上面，不会被遮挡

What is actually happening?

bug，提示框会被弹框遮挡