Resolve "Don't check confidential issues for spam"

What does this MR do?

Spam checks are meant for content that could be indexed by search engines. Confidential issues aren't indexed by search engines, so we don't need to do spam checks for them.

We do need to check for spam when an issue changes from confidential to public, even if nothing else changed.

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the style guides

Closes #56371 (closed).