Add test for binding with templatestring

Author: tronsha

tests/fixtures/vue-bind/binding-with-template-string-4.twig

@@ -0,0 +1,6 @@
+{% set foo = foo|default('') %}
+<div class="block {{ class|default('') }}" style="{{ style|default('') }}">
+  <div style="{{ foo ? foo : "width: " ~ size ~ "; height: " ~ size }}">
+    Foo
+  </div>
+</div>

tests/fixtures/vue-bind/binding-with-template-string-4.vue

@@ -0,0 +1,22 @@
+<template>
+  <div class="block">
+    <div :style="foo ? foo : `width: ${size}; height: ${size}`">
+      Foo
+    </div>
+  </div>
+</template>
+
+<script>
+  export default {
+      props: {
+        foo: {
+          type: String,
+          default: '',
+        },
+        size: {
+              type: Number,
+              required: true,
+          },
+      },
+  };
+</script>