LGTM.com - false positive - unused variable with vue setup script

**Description of the false positive**

When using the new [](https://vuejs.org/api/sfc-script-setup.html) in vue sfcs the top-level functions/variables are automatically exposed to the template.

Since they are not used inside the `<script>` lgtm.com marks them as unused, despite them being referenced from the template.

```vue
<template>
<button @click="log">{{ msg }}</button>
</template>

<script setup>
// variable
const msg = 'Hello!'

// functions
const log = () => {
console.log(msg)
}

```

**URL to the alert on the project page on LGTM.com**
https://lgtm.com/projects/g/rotki/rotki/snapshot/cc87af463bd9976f8ee7d090c770e7c79de61c7d/files/frontend/app/src/components/settings/general/QueryPeriodSettings.vue?sort=name&dir=ASC&mode=heatmap#x87a8976eef9f9886:1

Start with the referenced file, frontend/app/src/components/settings/general/QueryPeriodSettings.vue, and reproduce the alert for its Vue block. Then inspect the CodeQL JavaScript unused-variable analysis and its handling of template references; done means variables and functions exposed to the template are no longer reported as unused.

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