desktop: Launching with a URL which does not return a success causes Ruffle to hang

[colin969]

Describe the bug

When running the standalone player from command line and the location is a URL which does not return a success, the UI fails to load and the process will not exit. This will remain in the background until the shell dies or it's otherwise killed manually.

Expected behavior

Process should exit safely.

Content Location

Use https://example.com/game.swf for an easy example.

Affected platform

Desktop app

Operating system

Windows 11

Browser

No response

Additional information

2025-02-14T20:43:03.156287Z INFO ruffle_desktop::gui::controller: Using preferred backend Vulkan
2025-02-14T20:43:03.175049Z INFO ruffle_desktop::gui::controller: Using graphics API vulkan on AMD Custom GPU 0405 (type: IntegratedGpu)
2025-02-14T20:43:03.382448Z WARN egui_wgpu::renderer: Detected a linear (sRGBA aware) framebuffer Rgba8UnormSrgb. egui prefers Rgba8Unorm or Bgra8Unorm
2025-02-14T20:43:03.384077Z INFO ruffle_desktop::gui::controller: loaded cjk fallback font "ArialMT"
2025-02-14T20:43:03.404472Z INFO ruffle_video_external::decoder::openh264: Downloading OpenH264 library
2025-02-14T20:43:03.406663Z INFO ruffle_video_external::decoder::openh264: Using OpenH264 at "C:\Users\Colin\AppData\Local\ruffle\video\openh264-2.4.1-win64.dll"
2025-02-14T20:43:04.388919Z ERROR ruffle_frontend_utils::backends::executor: Async error: HTTP Status is not OK: HTTP status is not ok, got 404 Not Found redirected: 404