fix: align promise helper types and test playback rejections

test/utils.test.ts

@@ -0,0 +1,10 @@
+import type { Utils } from '../packages/artplayer/types/utils'
+
+export function checkSilencePromiseTypes(utils: Utils, thenable: PromiseLike<number>) {
+  const promise: Promise<number | undefined> = utils.silencePromise(Promise.resolve(42))
+  const synchronous: undefined = utils.silencePromise(undefined)
+  const unchanged: PromiseLike<number> = utils.silencePromise(thenable)
+  // @ts-expect-error A catch-less thenable is not converted to a native Promise.
+  utils.silencePromise(thenable).catch(() => {})
+  return { promise, synchronous, unchanged }
+}