Fix wasm_proxied_mount_css to not reuse an existing style element (#7709

)

* Fix wasm_proxied_mount_css to not reuse an existing style element but replace it for theme updates upon rerunning a new app

* add changeset

---------

Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>

.changeset/tiny-years-rest.md

@@ -0,0 +1,6 @@
+---
+"@gradio/app": patch
+"gradio": patch
+---
+
+fix:Fix wasm_proxied_mount_css to not reuse an existing style element

js/app/src/lite/css.ts

@@ -35,10 +35,11 @@ export async function wasm_proxied_mount_css(
 	});
 	const css = new TextDecoder().decode(response.body);
 
-	const existing_link = document.querySelector(
+	// Gradio Lite can be reloaded without refreshing the page, so we need to remove the existing style element if it exists.
+	const existing_style = document.querySelector(
 		`style[data-wasm-path='${url_string}']`
 	);
-	if (existing_link) return;
+	existing_style?.remove();
 
 	if (url.pathname === DYNAMIC_THEME_CSS_URL_PATH) {
 		console.debug(