thanos update to 15.9.1-bb.2

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/product/packages/thanos/-/blob/15.9.1-bb.2/CHANGELOG.md

Package MR

big-bang/product/packages/thanos!117 (merged)

For Issue

Closes issue

Upgrade Notices

N/A

Closes big-bang/product/packages/thanos#95 (closed)