Support sub tree as component props for mini-react and vue

[henrytao-me]

What?

Sub tree (fragment) as component props is supported in vanilla js and react since this PR #73. mini-react and vue need to have similar support as well.

Sample of sub tree in React (prefix prop):

import {useState, createContext, useContext, useEffect, useMemo} from 'react';
import {
  render,
  Button as ReactButton,
  Text as ReactText,
} from '@shopify/argo-checkout-react';

function App() {
  const [count, setCount] = useState(0);
  const [toggle, setToggle] = useState(true);

  return (
    <>
      <ReactButton
        fill
        onPress={() => setCount((count) => count + 1)}
        prefix={toggle && <ReactText>Prefix {count}</ReactText>}
      >
        Press me! ({count})
      </ReactButton>
      <ReactButton fill onPress={() => setToggle(!toggle)}>
        Toggle fragment
      </ReactButton>
    </>
  );
}
render('Checkout::KitchenSink', () => <App />);

[lemonmade]

mini-react and the dedicated Vue bindings have been removed as part of refactoring remote-ui onto the DOM.