fix: don't fetch emoji on client if server rendered

If you employ SSR (Server Side Rendering) in your Nuxt application, the module will inject the emoji `<svg>` or `<img>` element into the output code during your project's build/generate process. Alternatively, if SSR is not used, the emojis will dynamically render during client runtime.

src/runtime/components/Twemoji.vue

@@ -37,6 +37,7 @@ const fetchSVG = () => $fetch(emojiLinkSVG.value).then(async (res) => await res.
 const component = computed(() => defineComponent(components.value[parsed.value]))
 
 const loadSVG = async () => {
+  if (components.value[parsed.value]) return
   isFetching.value = true
   let svg = await fetchSVG()
   isFetching.value = false