Replace the danger-callout with help text

Problem to solve

Older danger-callout components are being used to share constraints with users for personal access tokens and ssh key expiration dates, which do not match guidelines in Pajamas.

Personal access tokens	SSH keys

Proposal

• Remove the danger-callout and replace with help text.
• Update the help and description text
• The date picker should prevent picking invalid dates. Should a user input an invalid date, they should get an error message

Personal access tokens	SSH keys