Added details to removal system notes

What does this MR do and why?

Updates system notes:

• "removed start/due date" becomes "removed start/due date date"
• "removed the health status" becomes "removed the health status health status"
• "removed iteration" becomes "removed iteration iteration reference"

(milestone system note is being addressed separately because of additional changes/complexity - !117529 (merged))

Related to #394779 (closed)

Screenshots or screen recordings

How to set up and validate locally

1. Go to issue show page
2. Remove the mentioned attributes
3. Check that "Removed ..." is added in system notes

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.