Update fastiron.rb enable prompt password regex

[pepperoni-pi]

Pre-Request Checklist

• Passes rubocop code analysis (try rubocop --auto-correct)
• Tests added or adapted (try rake test)
• Changes are reflected in the documentation
• User-visible changes appended to CHANGELOG.md

Description

Modified the password regex for the enable prompt. The previous regex did not match on models that prompt with "Enable Password:" instead of just "Password:".

[pepperoni-pi]

Checks appear to be failing due to PR #2377 which was already merged in to the master branch.