www/grafana8: Update to 8.5.20 (Fixes security vulnerabilities)

ChangeLog: https://grafana.com/docs/grafana/latest/whatsnew/

Fixes:

• Spoofing originalUrl of snapshots
• Stored XSS in ResourcePicker component

PR: 269409
Reported by: drtr0jan@yandex.ru (maintainer)
MFH: 2023Q1 (security fixes)
Security: CVE-2022-23552 CVE-2022-39324

(cherry picked from commit 71bbafdbe0f5df8c36aeade818e1375891644cf3)