backend: plugins: Remove .plugins from watch list

This fix prevents the development app (when running npm run dev-only-app) from watching for static plugins locally, which causes an endless loop of refreshes to the app.

Fixes: #1937

Signed-off-by: Evangelos Skopelitis <eskopelitis@microsoft.com>

backend/cmd/headlamp.go

@@ -312,7 +312,7 @@ func createHeadlampHandler(config *HeadlampConfig) http.Handler {
 
 	plugins.PopulatePluginsCache(config.staticPluginDir, config.pluginDir, config.cache)
 
-	if !config.useInCluster {
+	if !config.useInCluster && config.staticPluginDir != "" {
 		// in-cluster mode is unlikely to want reloading plugins.
 		pluginEventChan := make(chan string)
 		go plugins.Watch(config.pluginDir, pluginEventChan)