Create new UICommand instances to prevent stale input values

To be used in conjunction with https://github.com/forge/core/pull/505. Needs a new release of Forge-Core  when the dependent PR is merged.
Ah, I think we should no longer accept wizardTitle. I believe I'm populating the wizard title with the UICommand's name from it's metadata, in the `WizardDialogHelper.openWizard()` method. I'll clean this up.