compose_reply: Empty DM recipient box on forwarding message.

This fixes an accidental change introduced in #32578.

Forwarding a message and choosing DM should result in
an empty recipient box instead of showing current
recipients.

web/src/compose_reply.ts

@@ -263,7 +263,7 @@ export function quote_message(opts: {
             keep_composebox_empty: opts.keep_composebox_empty,
             content: quoting_placeholder,
             stream_id,
-            private_message_recipient_ids: people.pm_with_user_ids(message) ?? [],
+            private_message_recipient_ids: [],
         });
         compose_recipient.toggle_compose_recipient_dropdown();
     } else {