Adapt healthcheck to new metal-lib.

[Gerrit91]

No description provided.

[majst01]

Integration fails with:

2024-08-05T12:57:01.5945638Z panic: sync: negative WaitGroup counter
2024-08-05T12:57:01.5946283Z 
2024-08-05T12:57:01.5946562Z goroutine 1408 [running]:
2024-08-05T12:57:01.5947172Z sync.(*WaitGroup).Add(0x0?, 0x0?)
2024-08-05T12:57:01.5947770Z 	/opt/hostedtoolcache/go/1.22.5/x64/src/sync/waitgroup.go:62 +0xd8
2024-08-05T12:57:01.5948409Z sync.(*WaitGroup).Done(...)
2024-08-05T12:57:01.5948938Z 	/opt/hostedtoolcache/go/1.22.5/x64/src/sync/waitgroup.go:87
2024-08-05T12:57:01.5950225Z github.com/metal-stack/metal-api/cmd/metal-api/internal/grpc.(*test).waitForAllocation(0xc000498c00, {0x1065216, 0x1}, {0x126d300, 0xc0005f6080}, {0x1268c70, 0xc0003c5c20})
2024-08-05T12:57:01.5951789Z 	/home/runner/work/metal-api/metal-api/cmd/metal-api/internal/grpc/boot-service-wait_integration_test.go:313 +0x1bc
2024-08-05T12:57:01.5952920Z github.com/metal-stack/metal-api/cmd/metal-api/internal/grpc.(*test).startMachineInstances.func1()
2024-08-05T12:57:01.5954129Z 	/home/runner/work/metal-api/metal-api/cmd/metal-api/internal/grpc/boot-service-wait_integration_test.go:268 +0xa8
2024-08-05T12:57:01.5955443Z created by github.com/metal-stack/metal-api/cmd/metal-api/internal/grpc.(*test).startMachineInstances in goroutine 38
2024-08-05T12:57:01.5956708Z 	/home/runner/work/metal-api/metal-api/cmd/metal-api/internal/grpc/boot-service-wait_integration_test.go:266 +0x12d
2024-08-05T12:57:01.5962232Z FAIL	github.com/metal-stack/metal-api/cmd/metal-api/internal/grpc	7.351s
2024-08-05T12:57:01.6012433Z ?   	github.com/metal-stack/metal-api/cmd/metal-api/internal/headscale	[no test files]
2024-08-05T12:57:01.6013613Z ?   	github.com/metal-stack/metal-api/cmd/metal-api/internal/ipam	[no test files]

[Gerrit91]

Integration tests became really unstable... took five retries. :(