Update CHANGELOG

Author: matthiasgeihs

packages/shield-controller/CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add two new controller state metadata properties: `includeInStateLogs` and `usedInUi` ([#6504](https://github.com/MetaMask/core/pull/6504))
 - Add signature coverage checking ([#6501](https://github.com/MetaMask/core/pull/6501))
 - Add transaction and signature logging ([#6633](https://github.com/MetaMask/core/pull/6633))
+- Log `not_shown` if result is not available ([#6667](https://github.com/MetaMask/core/pull/6667))
 
 ### Changed