web: Don't try to connect to an unsupported URL

If Ruffle recognises that a URL is invalid or not supported, it now
doesn't try to connect to it, but instantly panics.
This reduces unnecessary connection attempts and improves reaction
speed.

Author: Korne127

web/packages/core/src/ruffle-player.tsx

@@ -2055,6 +2055,11 @@ export class RufflePlayer extends HTMLElement {
         this.container.prepend(div);
     }
 
+    public displayRootMovieUnsupportedUrlMessage(unsupportedUrl: string) {
+        this.swfUrl = new URL(unsupportedUrl, document.baseURI);
+        this.displayRootMovieDownloadFailedMessage(false);
+    }
+
     protected displayRootMovieDownloadFailedMessage(invalidSwf: boolean): void {
         const openInNewTab = this.loadedConfig?.openInNewTab;
         if (

web/packages/extension/src/player.ts

@@ -123,6 +123,10 @@ async function load(options: string | DataLoadOptions | URLLoadOptions) {
     }
 
     const supportedURL = utils.supportedURL(url);
+    if (!supportedURL && urlString) {
+        player.displayRootMovieUnsupportedUrlMessage(urlString);
+        return;
+    }
     if (
         supportedURL &&
         !(await utils.hasHostPermissionForSpecifiedTab(origin!))