Fix status reporting for invalid HTTPRoutes

[pleshakov]

918d650 introduced a bug which made NKG fail to report status conditions for an invalid HTTPRoute. It would try to report an empty condition in the status and fail because of the status CRD validation (example error):

{"level":"error","ts":"2023-04-18T15:37:49Z","logger":"statusUpdater","msg":"Failed to update status","namespace":"default","name":"coffee","kind":"HTTPRoute","error":"HTTPRoute.gateway.networking.k8s.io \"coffee\" is invalid: [status.parents[0].conditions[1].reason: Invalid value: \"\": status.parents[0].conditions[1].reason in body should be at least 1 chars long, status.parents[0].conditions[1].status: Unsupported value: \"\": supported values: \"True\", \"False\", \"Unknown\", status.parents[0].conditions[1].type: Invalid value: \"\": status.parents[0].conditions[1].type in body should match '^([a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*/)?(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])$']","stacktrace":"github.com/nginxinc/nginx-kubernetes-gateway/internal/status.(*updaterImpl).update\n\t/home/runner/work/nginx-kubernetes-gateway/nginx-kubernetes-gateway/internal/status/updater.go:168\ngithub.com/nginxinc/nginx-kubernetes-gateway/internal/status.(*updaterImpl).Update\n\t/home/runner/work/nginx-kubernetes-gateway/nginx-kubernetes-gateway/internal/status/updater.go:128\ngithub.com/nginxinc/nginx-kubernetes-gateway/internal/events.(*EventHandlerImpl).HandleEventBatch\n\t/home/runner/work/nginx-kubernetes-gateway/nginx-kubernetes-gateway/internal/events/handler.go:90\ngithub.com/nginxinc/nginx-kubernetes-gateway/internal/events.(*EventLoop).Start.func1.1\n\t/home/runner/work/nginx-kubernetes-gateway/nginx-kubernetes-gateway/internal/events/loop.go:67"}

This PR fixes that bug.