Add type annotation for some js files (#24787)

app/javascript/mastodon/compare_id.ts

@@ -0,0 +1,11 @@
+export default function compareId (id1: string, id2: string) {
+  if (id1 === id2) {
+    return 0;
+  }
+
+  if (id1.length === id2.length) {
+    return id1 > id2 ? 1 : -1;
+  } else {
+    return id1.length > id2.length ? 1 : -1;
+  }
+}