Group and Projects - Permanent Deletion Date Followups

What / Why

Follow up from threads on !148997 (merged)

• Nit (non-blocking): Would be nice to use a proper translation here instead of the custom string interpolation
• Nit (non-blocking): The call to the helper is pretty long and repeated twice so would be nice to extract it to a variable date or deletion_date on the top of the partial (like the other HAML files)
• Nit (non-blocking): Same comment about a variable.
• Update date addition

Proposal

Address these small followups to cleanup some of the existing code related to these permanent deletion messages.