chore(custom-chart-web): update changelog

Author: samuelreichert

packages/pluggableWidgets/custom-chart-web/CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+### Fixed
+
+- We fixed an issue with incorrect parsing and merging of layout and data properties.
+
 ## [1.2.0] - 2025-06-03
 
 ### Changed