fix: avoid creating unnnecessary deriveds for text nodes with call

[paoloricciuti]

Svelte 5 rewrite

As per #13171 (comment) we were creating unnecessary deriveds in the compiled code.

This was a bit tricky to fix because in the RegularElement visitor we call build_template that if there's more than one call creates this deriveds and push them to the init. However in RegularElement if we realise that there's state the template that we just built is unused and we proceed to process the children which calls build_template again creating another set of deriveds (which this time will be actually pushed to the update).

To fix this i've splitted the logic to check how many states/calls are there in it's own function (used by build_template) so that i can use that function instead in RegularElement.

I went with snapshot tests because that's just unused code.

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