fix: carry draft attachments in the Pro draft tab too

The #849 fix carries a re-opened draft's parts into the composer on the
classic path, but the Pro draft tab builds its own initialData and
still omitted email.attachments - editing a draft from a Pro tab kept
stripping its files on the next save. Pass the parts through; the
composer's existing initializer and remap handle the rest.

components/pro/pro-email-tab-body.tsx

@@ -324,6 +324,10 @@ export function ProEmailTabBody({ tabId, data }: ProEmailTabBodyProps) {
         subAddressTag: '',
         mode: 'compose',
         draftId: email.id,
+        // The draft's already-uploaded parts - the classic path carries them
+        // since #849; without this the Pro draft tab still opened the
+        // composer without its files and the next save stripped them.
+        attachments: email.attachments,
       },
     });
     closeTab(tabId);