istio: remove server header via envoyfilter

Package Owner Merge Request

Package Changes

Removes server response header to prevent information disclosure

https://repo1.dso.mil/platform-one/big-bang/apps/core/istio-controlplane/-/merge_requests/63

https://repo1.dso.mil/platform-one/big-bang/apps/core/istio-controlplane/-/releases/1.10.3-bb.1

Additional Details

Closes #241 (closed)