refactor: update gradient function call in app.component.html and rem…

…ove unused background style binding

fix: change event parameter type in logEvent method of DetectChangeExampleComponent
chore: remove unused test.ts file and move Direction type definition to ngx-colors-trigger.directive.ts

chore: add changelog entry for version 4.0.3 with internal cleanup de…

…tails

Co-authored-by: Copilot <copilot@github.com>