Limit snippet blob height to 500px

What does this MR do and why?

This limits the height of a snippet blob (when viewed) to 500px. It is the same height like the blob editor when you edit a snippet.

Screenshots or screen recordings

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #255175 (closed)