Remove CHANGELOG entry

Author: matthiasgeihs

packages/keyring-controller/CHANGELOG.md

@@ -7,10 +7,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-### Changed
-
-- Upgrade mock encryptor to support multiple ciphertexts ([#5943](https://github.com/MetaMask/core/pull/5943))
-
 ## [22.0.2]
 
 ### Fixed