Remove nested form tag in WorkerConfiguration modal

Closes #1034 (closed)

The WorkerConfiguration modal is in the Configurations/List.vue component. This component uses the Create.vue component to show a creation form, which contains a <form> tag with a v-on:submit.prevent to prevent #1034 (closed) from happening. But this component itself uses Form.vue, which has a <form> with no event handling in it. When the user configuration is in use (when there is more than just the raw JSON payload), a second nested <form> was also present. I removed the first <form> since Vue 3 allows doing that, and replaced the second one with a <div>.