Removed un-used file

What does this MR do?

/app/views/shared/snippets/show.js.haml seems to be not used in the codebase anymore and it's safe to remove it.

Screenshots

No visual changes

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

References #250840