[LiveComponent] Only consider Live components in InterceptChildComponentRenderSubscriber

[sneakyvv]

Q	A
Bug fix?	yes
New feature?	no
Tickets
License	MIT

This PR is related to the change of #1093.

Problem

The component stack now also contains embedded Components until they are fully rendered, which is good. But, that also means that with this setup

{# someTemplate #}

<twig:aLiveComponent>
    <twig:aTwigComponent>
        <twig:anotherLiveComponent>
            {# ... #}
        </twig:anotherLiveComponent>
    </twig:aTwigComponent>
</twig:aLiveComponent>

when re-rendering the anotherLiveComponent the InterceptChildComponentRenderSubscriber would look at the parent component's childrenFingerprints to determine if it can short-circuit the rendering process for anotherLiveComponent and return an empty html element causing the FE to not do a callback to re-render it. However since that parent is a non-live component it will never short-circuit.

Solution

Only take live components into account.

[weaverryan]

Thanks Bart!