CP-14150 - Stop double-showing field help text on mobile

What
Field descriptions (hints) now appear only once on mobile signing forms

Why
On mobile, the same description was rendered in the field header and again under the field, making instructions look duplicated and harder to read

How to test
1. Open a form on a mobile viewport with a field that has a description/hint
2. Confirm the help text shows once (under the field), not twice
3. Spot-check desktop: help text still shows once
4. Confirm fields without a hint look unchanged

Author: bernardodsanderson

app/javascript/submission_form/form.vue

@@ -158,13 +158,6 @@
             ({{ t('optional') }})
           </span>
         </div>
-        <div
-          v-if="currentField?.description"
-          class="mt-2 text-base text-base-content/80"
-          dir="auto"
-        >
-          <MarkdownContent :string="currentField.description" />
-        </div>
       </div>
       <form
         v-if="!isCompleted && !isInvite"