feat(DesignTokens): add text warning design tokens

mentioned in commit 605d53b5

mentioned in merge request gitlab-org/editor-extensions/gitlab-jetbrains-plugin!999 (merged)

mentioned in merge request status-page!903

mentioned in merge request gitlab!166552 (merged)

mentioned in merge request gitlab!166770 (closed)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!4067 (closed)

mentioned in merge request gitlab-org/frontend/pajamas-adoption-scanner!349 (merged)

mentioned in merge request gitlab-org/frontend/playground/accessibility-scanner!51 (merged)