chore(vue3): remove incorrect <template> tag in tests

What does this MR do?

Vue2 treats template tag without extra attributes quite similar to DocumentFragment - simply ignores it. In Vue3, however, this behavior changed to one making more sense - <template> tag without extra vue-specific inside of the component (not on root level) is treated as HTML5 <template> tag (sounds logical, huh?)

This MR removes usage of such <template> in our test suite

This is forward-compatible change to support @vue/compat #1981 (closed)

Does this MR meet the acceptance criteria?

Conformity

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• Added the ~"component:*" label(s) if applicable.

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