update thanos to 15.9.1-bb.1

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/product/packages/thanos/-/blob/main/CHANGELOG.md

Package MR

big-bang/product/packages/thanos!114 (merged)

For Issue

Closes big-bang/product/packages/thanos#91 (closed)

Upgrade Notices

N/A