DEV: Draft check async when starting new PM

When the sequence is missng, the draft check is done synchronously and it results in  iOS devices not launching the keyboard.

app/assets/javascripts/discourse/app/routes/application.js

@@ -85,6 +85,7 @@ const ApplicationRoute = DiscourseRoute.extend(OpenComposer, {
         recipients,
         archetypeId: "private_message",
         draftKey: Composer.NEW_PRIVATE_MESSAGE_KEY,
+        draftSequence: 0,
         reply,
         title
       });