fix: prevent iOS crash when audio download fails in playFromUrl

[bradrice]

Problem

On iOS, TNSPlayer.playFromUrl crashes when the audio download fails. In the NSURLSession.dataTaskWithURLCompletionHandler callback, an error is handled by rejecting the promise — but execution does not stop, so it falls through to:

if (error !== null) {
    if (this.errorCallback) {
        this.errorCallback({ error });
    }
    reject(error);          // ← no return
}
const errorRef = new interop.Reference<NSError>();
const inputSource = SFBInputSource.inputSourceWithData(data);  // data is null → crash

When the request errors, data is null, so SFBInputSource.inputSourceWithData(data) (and the decoder init that follows) runs on invalid data and crashes the app. This shows up in practice as a crash/error when navigating away mid-load or when a track fails to download.

Fix

Return after rejecting so the handler bails out cleanly on error:

-                        reject(error);
+                        return reject(error);

One line, src/audio/player.ios.ts. The other error branches in this handler already return reject(...); this makes the download-error branch consistent with them.

Testing

We've been running this exact change in production (iOS) via patch-package against @nativescript-community/audio@6.4.14, and it resolves the crash. The change is a control-flow guard only — no behavior change on the success path.