[Bug Report][2.5.3] v-select doesn't display placeholder when setting persistent-placeholder

[LazyLZ]

Environment

Vuetify Version: 2.5.3
Vue Version: 2.6.14
Browsers: Chrome 91.0.4472.106
OS: Windows 10

Steps to reproduce

for any Browser or system, use both placeholder and persistent-placeholder on v-select. The placeholder doesn't display until clicked

Expected Behavior

show placeholder before clicked

Actual Behavior

The placeholder doesn't display until clicked

Reproduction Link

https://codepen.io/lazylz/pen/XWMoKZW?editors=101