http: fix camera/label/snapshot.jpg caching (#9811)

[lawm]

... by returning at most max-age=60 #9811

Tested by fetching snapshot.jpg, inspecting response headers, and seeing new event's snapshot

[netlify[bot]]

✅ Deploy Preview for frigate-docs ready!

Name	Link
🔨 Latest commit	113b8394de96a062e025986bb546728b58f440f1
🔍 Latest deploy log	https://app.netlify.com/sites/frigate-docs/deploys/65c94aa93f94400008000200
😎 Deploy Preview	https://deploy-preview-9812--frigate-docs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[lawm]

actually, doesn't seem to work. I don't see the ongoing event snapshot.

[lawm]

The commit works to change the Cache setting. Maybe ongoing events aren't inserted in the DB yet when I fetch the snapshot. I'm not sure. It doesn't solve my issue, but the commit could be merged.