[form-input, form-textarea] update examples to remove field

[neilpfeiffer]

Feature Request

Description

Generated from here: #3075 (comment)

Remove the Field from the examples for form-input and form-textarea, so users do not get confused what they are seeing and testing, compared to the InputField and TextareaField
The use of Field around the solo/basic components is now duplicative, since these example originally did not have the example template housing it, which now provides its own title and appropriate descriptions.

Related (but not resolved in this issue)

As part of our best practice UX Audits, it was identified that UX would like to showcase the InputField and other Field componsitions as the primary form components, and then either move or segment raw building block components, like the solo input element component, into a separate location. See: UX Audit: terra-form-input