Use route's first defined format as default

instead of PNG

discord/cdn_endpoints.go

@@ -104,7 +104,7 @@ func (e CDNEndpoint) URL(format FileFormat, values QueryValues, params ...any) s
 
 func DefaultCDNConfig() *CDNConfig {
 	return &CDNConfig{
-		Format: FileFormatPNG,
+		Format: FileFormatNone,
 		Values: QueryValues{},
 	}
 }
@@ -137,6 +137,9 @@ func WithFormat(format FileFormat) CDNOpt {
 
 func formatAssetURL(cdnRoute *CDNEndpoint, opts []CDNOpt, params ...any) string {
 	config := DefaultCDNConfig()
+	// use the first provided format in the route definition itself. if the user provides a different format, this will be overriden by the Apply function call below
+	// previously, the default format was png, which would cause issues for cdn endpoints like attachments and soundboard sounds, requiring custom "overrides"
+	config.Format = cdnRoute.Formats[0]
 	config.Apply(opts)
 
 	var lastStringParam string