feat(Wizard - next): supporting component unit tests

[jpuzz0]

Depends on: #7703

Added unit tests for the following:

• WizardFooter
• WizardStep
• WizardToggle
• WizardBody

Note:

• WizardComposableContext, although is implicitly somewhat tests via WizardComposable tests, since more changes are planned for it, any explicit tests will be deferred to a separate task.

In addition:

• Bubbled up a prop for controlling the mount/unmount state of inactive steps to WizardComposable as well.