PDF Settings - Confirmation on unsaved settings.

[jestonihpi]

Description Gravity Forms provides a pop up for unsaved settings. I think we should also introduce this on our end.

Step To Reproduce Steps to reproduce the behavior:

1. Go to 'PDF settings (Global or Form)'
2. Update any options
3. Refresh or Go to any page.
4. See error

Expected behavior An alert box should pop up when you leave your unsaved settings.

Screenshots If applicable, add screenshots to help explain your problem.

Additional context This is to inline the general UX with Gravity Form.

[jakejackson1]

@debbieellis7 this would be a nice feature to add