Use embed_dropdown for snippets

What does this MR do?

This MR replaces the embed input used in snippets with a compact dropdown that mirrors it's "Clone" counterpart.

Screenshots

Before	After	Compared to Clone

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

• Related to #220803 (closed)