Don't panic if plugin manifest does not have settings (#9086)

app/plugin_api.go

@@ -32,9 +32,11 @@ func (api *PluginAPI) LoadPluginConfiguration(dest interface{}) error {
 	finalConfig := make(map[string]interface{})
 
 	// First set final config to defaults
+	if api.manifest.SettingsSchema != nil {
 		for _, setting := range api.manifest.SettingsSchema.Settings {
 			finalConfig[strings.ToLower(setting.Key)] = setting.Default
 		}
+	}
 
 	// If we have settings given we override the defaults with them
 	for setting, value := range api.app.Config().PluginSettings.Plugins[api.id] {