Plugins: Add referer and user login params to plugin CDN redirect logs (#77942)

add referer and user

pkg/api/plugins.go

@@ -380,6 +380,8 @@ func (hs *HTTPServer) redirectCDNPluginAsset(c *contextmodel.ReqContext, plugin
 		"pluginVersion", plugin.Info.Version,
 		"assetPath", assetPath,
 		"remoteURL", remoteURL,
+		"referer", c.Req.Referer(),
+		"user", c.Login,
 	)
 	pluginsCDNFallbackRedirectRequests.With(prometheus.Labels{
 		"plugin_id":      plugin.ID,