grafana update to 10.5.15-bb.1

Package Merge Request

Update includes changes to generate Grafana's Istio resources with bb-common

Package Changes

https://repo1.dso.mil/big-bang/product/packages/grafana/-/blob/10.5.15-bb.1/CHANGELOG.md

Package MR

big-bang/product/packages/grafana!231 (merged)

For Issue

Closes issue

Upgrade Notices

N/A