Draft: istio update to 1.21.1-bb.0

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/product/packages/istio-controlplane/-/blob/1.21.1-bb.0/CHANGELOG.md

Package MR

big-bang/product/packages/istio-controlplane!213 (merged)

For Issue

big-bang/product/packages/istio-controlplane#143 (closed)

Upgrade Notices

N/A