Remove no longer used incubation alert component
What does this MR do and why?
Removes the incubation alert files that are no longer used:
app/assets/javascripts/vue_shared/components/incubation/incubation_alert.vue
spec/frontend/vue_shared/components/incubation/incubation_alert_spec.js
MR acceptance checklist
Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.
Screenshots or screen recordings
No visual changes
How to set up and validate locally
Numbered steps to set up and validate the change are strongly suggested.
Related to #497751
Edited by Ezekiel Kigbo