Remove sticky reference on beforeDestroy

What does this MR do?

Relates to: #39145 (closed)

Removes polyfillSticky when diff_header is being destroyed.

Screenshots

n/a

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