`vscode.openFolder`: treat missing URI schema gracefully (for #55891)

src/vs/workbench/api/node/apiCommands.ts

@@ -49,7 +49,8 @@ export class OpenFolderAPICommand {
 			return executor.executeCommand('_files.pickFolderAndOpen', forceNewWindow);
 		}
 		if (!uri.scheme) {
-			throw new Error(`Invalid URI, schema required: '${uri.toString()}'.`);
+			console.warn('`vscode.openFolder` command invoked with an invalid URI (scheme missing): `${uri}`. Converted to a `file://` URI.');
+			uri = URI.file(uri.fsPath);
 		}
 
 		return executor.executeCommand('_files.windowOpen', [uri], forceNewWindow);