Remove dead code: unused tick_formats.js file

What does this MR do?

Since the rewriting of the contributors charts to use echarts and vue at !16677 (diffs) tick_formats became dead code.

This MRs removes this file and it's spec.

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