MFXStepper validators dialog

[Hdiyja]

Describe the bug
I am having trouble accessing the error information for my MFXSteppers. When clicking on the triangle icon next to the MFXStepperToggle icon, I instead get the following error: https://pastebin.com/FB0npTpY

Minimal Reproducible Example

• I wanted to attach it to the issue, but after trying to do the same thing in the latest demo release, the bug is actually there in the demo too. For context, I'm talking about the windows demo, I haven't tested it on Linux nor Mac

To Reproduce
Steps to reproduce the behavior:

1. Open a stepper
2. Do something against the validator set up (in the case of the demo, just insert no username or a username with < 6 characters)
3. Click on the yellow triangle next to the steppertoggle icon

Expected behavior
A dialog should've popped up, explaining what the end user did wrong in selecting username/password.