Add support for multi-line text in `<FormRow>`

### Description

We have a couple places in the UI where a `` component is used within a `<FormRow>`.

That is achieved using the `input` placeholder to provide a custom `<textarea>` component inside the row.

For example:
```
<FormRow v-model="input.options.cert">
X.509 Certificate Public Key
<template #input><textarea class="font-mono w-full" rows="6" v-model="input.options.cert">

```

Given we now have two places that need to do this, we run the risk of getting a third and a fourth, which then becomes multiple places to update if we want to change the styling etc.

We should consider adding `` as one of the built-in options for FormRow.