same protocol as hf spaces for iframe postMessage

src/lib/components/InferencePlayground/InferencePlaygroundModelSelector.svelte

@@ -35,7 +35,9 @@
 		url.searchParams.set("modelId", model.id);
 
 		const parentOrigin = "https://huggingface.co";
-		window.parent.postMessage({ modelId: model.id }, parentOrigin);
+		const searchParamsWithoutTheme = new URLSearchParams(url.searchParams.toString());
+		searchParamsWithoutTheme.delete("__theme");
+		window.parent.postMessage({ queryString: searchParamsWithoutTheme.toString() }, parentOrigin);
 
 		goto(url.toString(), { replaceState: true });
 	}