fix: use png as extension for defaultAvatarURL (#7414)

Author: herrtxbias

packages/rest/__tests__/CDN.test.ts

@@ -37,7 +37,7 @@ test('channelIcon default', () => {
 });
 
 test('defaultAvatar default', () => {
-	expect(cdn.defaultAvatar(defaultAvatar)).toBe(`${base}/embed/avatars/${defaultAvatar}.webp`);
+	expect(cdn.defaultAvatar(defaultAvatar)).toBe(`${base}/embed/avatars/${defaultAvatar}.png`);
 });
 
 test('discoverySplash default', () => {

packages/rest/src/lib/CDN.ts

@@ -113,7 +113,7 @@ export class CDN {
 	 * @param discriminator The discriminator modulo 5
 	 */
 	public defaultAvatar(discriminator: number): string {
-		return this.makeURL(`/embed/avatars/${discriminator}`);
+		return this.makeURL(`/embed/avatars/${discriminator}`, { extension: 'png' });
 	}
 
 	/**