fix: add missing email reply validation (#1934)

## Description

General fixes to the email domain features

Changes made:
- Add "email" validation for "Reply-To email" fields
- Fix issue where you can't remove the "Reply-To" email after it's set
- Fix issue where setting the "Sender email" back to Documenso would
still send using the org/team pref

packages/lib/server-only/recipient/delete-document-recipient.ts

@@ -130,7 +130,7 @@ export const deleteDocumentRecipient = async ({
         type: 'team',
         teamId: document.teamId,
       },
-      meta: document.documentMeta || null,
+      meta: document.documentMeta,
     });
 
     const [html, text] = await Promise.all([