add changelog entry for #4519

Author: midigofrank

CHANGELOG.md

@@ -27,6 +27,8 @@ and this project adheres to
 - Migrate form error display from `phx-feedback-for` to `used_input?/1` so
   validation errors only appear on fields the user has interacted with
   [#4472](https://github.com/OpenFn/lightning/pull/4472)
+- Fix sandbox name validation errors appearing twice
+  [#4490](https://github.com/OpenFn/lightning/issues/4490)
 - Isolate AI assistant tests with per-module manual Oban mode to prevent side
   effects leaking into concurrent tests
   [#4493](https://github.com/OpenFn/lightning/pull/4493)