drafts: Separate initialize function into data and UI pieces.

This will let us initialize the data before the UI is ready
to be initialized. We'll need to do this in an upcoming commit
where we clear a flag on page load before the reload code
initializes.

web/src/drafts.ts

@@ -622,6 +622,8 @@ export function initialize(): void {
     window.addEventListener("beforeunload", () => {
         update_draft();
     });
-
-    set_count(Object.keys(draft_model.get()).length);
+}
+
+export function initialize_ui(): void {
+    set_count(draft_model.getDraftCount());
 }