Restore original height after copy to clipboard button is clicked

[stefano-ottolenghi]

Fix #132, result:

(it makes sense to set the width a few lines earlier, or the Success button gets shrunk).

[netlify[bot]]

❌ Deploy Preview for neo4j-docs-ui failed.

Name	Link
🔨 Latest commit	cc30d06859f0ad151a7bfa634119f45f27a855ef
🔍 Latest deploy log	https://app.netlify.com/sites/neo4j-docs-ui/deploys/6386ef2a1eed13000860b8f6