feat: webp convert @frontend (#11150)

* webp convert @frontend

* 0.85 → 0.90

---------

Co-authored-by: tamaina <tamaina@hotmail.co.jp>

packages/frontend/src/scripts/upload/isWebpSupported.ts

@@ -0,0 +1,10 @@
+let isWebpSupportedCache: boolean | undefined;
+export function isWebpSupported() {
+	if (isWebpSupportedCache === undefined) {
+		const canvas = document.createElement('canvas');
+		canvas.width = 1;
+		canvas.height = 1;
+		isWebpSupportedCache = canvas.toDataURL('image/webp').startsWith('data:image/webp');
+	}
+	return isWebpSupportedCache;
+}