Merged native and mandrel checks

Since Quarkus 2.14.1, Mandrel builder image is the default image use.

https://quarkus.io/blog/quarkus-2-14-1-final-released/#mandrel-by-default

They do not use GraalVM anymore, so we don't need mandrel & native checks.

Changes:

• `native` will test so with mandrel image directly
• remove `mandrel` check
• rename `mandrel-lts` to `native-lts`