BadUserAccessDenied: when reconnecting to the service using the opcua-simulator

[libingke]

During reconnection, this function encryptPasswords(userIds) should not be executed multiple times.

ioTSensorsOPCUA/services/uaSrvService.go

...
server.WithAuthenticateUserNameIdentityFunc(func(
        encryptPasswords(userIds)
...

fix: like this

var once sync.Once
...
once.Do(func() {
        encryptPasswords(userIds)
})