@uppy/utils: migrate RateLimitedQueue to TS

[Murderlon]

Since we are not doing #4173 for #4764, it's better to have it typed if the code is sticking around for a while.

[github-actions]

Diff output files

diff --git a/packages/@uppy/utils/lib/RateLimitedQueue.js b/packages/@uppy/utils/lib/RateLimitedQueue.js
index 6d34ffa..4c49f99 100644
--- a/packages/@uppy/utils/lib/RateLimitedQueue.js
+++ b/packages/@uppy/utils/lib/RateLimitedQueue.js
@@ -276,17 +276,17 @@ function _next2() {
     return;
   }
   const next = _classPrivateFieldLooseBase(this, _queuedHandlers)[_queuedHandlers].shift();
+  if (next == null) {
+    throw new Error("Invariant violation: next is null");
+  }
   const handler = _classPrivateFieldLooseBase(this, _call)[_call](next.fn);
   next.abort = handler.abort;
   next.done = handler.done;
 }
 function _queue2(fn, options) {
-  if (options === void 0) {
-    options = {};
-  }
   const handler = {
     fn,
-    priority: options.priority || 0,
+    priority: (options == null ? void 0 : options.priority) || 0,
     abort: () => {
       _classPrivateFieldLooseBase(this, _dequeue)[_dequeue](handler);
     },