fix: frps plugin manager (#1803)

models/plugin/server/manager.go

@@ -52,7 +52,7 @@ func (m *Manager) Register(p Plugin) {
 		m.pingPlugins = append(m.pingPlugins, p)
 	}
 	if p.IsSupport(OpNewWorkConn) {
-		m.pingPlugins = append(m.pingPlugins, p)
+		m.newWorkConnPlugins = append(m.newWorkConnPlugins, p)
 	}
 	if p.IsSupport(OpNewUserConn) {
 		m.newUserConnPlugins = append(m.newUserConnPlugins, p)