Change logic behind "new" issues highlight

What does this MR do?

Change issue new? behavior:

1. Issues that are less than 24 hours old are new.
2. It does not matter if creation and edit dates are different.

Changes the green highlight of new issues from using today? to using new?

Fixes #233045 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content