Remove ignoring health_status from Epic

What does this MR do?

We

• added the ignore_column in 12.9
• we removed the column in 12.10

Now we can finally remove ignore_column from the code

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

Closes #209749 (closed)