Respect snippet query params when displaying embed urls

What does this MR do?

Changes the app/assets/javascripts/snippet/snippet_embed.js script to respect snippet query params when toggling between embed urls in the snippet show view.

Previously, if the snippet url is like /snippets/1?token=a, when the user toggles between Share and Embed urls, the param token=a will be removed from the resulting url.

Closes #38015 (closed) and #35095 (closed)

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