docs: remove all changelog changes per reviewer feedback

Agent-Logs-Url: https://github.com/MetaMask/metamask-mobile/sessions/1e063ea2-41d4-41b3-b54c-5dd4d0421c17

Co-authored-by: amitabh94 <12572750+amitabh94@users.noreply.github.com>

Author: Copilot

CHANGELOG.md

@@ -7,10 +7,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-### Changed
-
-- Made the Ramp Headless Host invisible so consumer-rendered loading UI is visible during a headless buy; added a transparent `RAMP.HEADLESS_ENTRY` outer route so the headless flow no longer renders an opaque V2 stack card on top of the consumer screen (Phase 9.5).
-
 ## [7.76.3]
 
 ### Added