Improve required error message if the form item does not have a label

[evshi]

Is your feature request related to a problem? Please describe.
If the form item does not have a label, then the required message includes the formItem ID, which is usually not user friendly.

Describe the solution you'd like
If the label is empty, then the required message should be updated to a nicer generic message, i.e. "Please enter a value"

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.