feat(Alert): Update design to match new design vision

See merge request !4496



Merged-by: Scott de Jonge <sdejonge@gitlab.com>
Approved-by: Jeremy Elder <jelder@gitlab.com>
Approved-by: Denys Mishunov <dmishunov@gitlab.com>
Approved-by: Scott de Jonge <sdejonge@gitlab.com>
Reviewed-by: Sascha Eggenberger <seggenberger@gitlab.com>
Reviewed-by: Scott de Jonge <sdejonge@gitlab.com>
Co-authored-by: Sascha Eggenberger <seggenberger@gitlab.com>

# [90.5.0](v90.4.0...v90.5.0) (2024-08-28)

### Features

* **Alert:** Update design to match new design vision ([27a6f982](27a6f982))