[Bug Report][3.6.10] v-menu attach

[chunlampang]

Environment

Vuetify Version: 3.6.10
Last working version: 3.6.8
Vue Version: 3.4.31
Browsers: Chrome 126.0.0.0
OS: Windows

Steps to reproduce

Just input v-menu attach as document said

Expected Behavior

No error

Actual Behavior

Failed to execute 'appendChild' on 'Node': Only one element on document allowed.

Reproduction Link

https://play.vuetifyjs.com/#...

[donalmurtagh]

The same error occurs in the latest release (v3.6.11) when you show a v-dialog if the value of the attach prop is anything other that the default value of false.

Here's a demo that reproduces the bug for v-dialog

• If :attach="false" (the default value), no error occurs
• If teleporting is disabled with :attach="true", the error occurs
• If we try to attach to a specific element e.g. attach=".dialog-target", the same error occurs

The error message that appears within the play demo is

Cannot read properties of undefined (reading 'classList')

According to the console error, the cause of the problem is an attempt to append the dialog to the document itself

DOMException: Failed to execute 'appendChild' on 'Node': Only one element on document allowed.

I suspect this issue and #20001 are related.