TransitionGroup should sniff for Teleport

[rtcpw]

There is an existing completed issue #5836 for making Transition component sniff out nested Teleport. This work has already been completed, but only for the Transition component. Would it be possible to add the same treatment to the TransitionGroup component, to keep the behavior consistent?

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Use case:

I am rendering a list of renderless components that use a root-level Teleport inside of them to render their content elsewhere in the DOM. It would be great if I could wrap the v-for in a TransitionGroup and have the animation play for all of the teleported elements. Currently, I am getting a warning Component inside <Transition> renders non-element root node that cannot be animated. when attempting to do just that (and no animation plays), while the same thing is supported with the Transition component when rendering single components.