Wildcard: `Form` migration

Created by: umpox

Context

We have a variety of usage of <form> in the Sourcegraph codebase:

• import { Form } from '@sourcegraph/branded/src/components/Form
• import { Form } from 'reactstrap
• Native <form> HTML element

We should align these to use a new Wildcard <Form> element.

Implementation

1. Wait for https://github.com/sourcegraph/sourcegraph/issues/32127 to be completed
2. Migrate remaining usage of other form elements in the codebase