update openapi spec for healthcheck

[FrankVisuals]

The healthcheck api did not match documentation, I will open a separate PR for the docs repository.

NOTE: I could not get the generation of the openapi.yml working and therefore made this small change manually. php artisan openapi did not apply the change I've done.

Changes

• updated the openapi.yml with the correct API path
• updated the openapi annotation on the healthcheck with the correct path

Issues

• as posted on discord

[andrasbacsai]

Thank you for the PR!