go tool directive issues

*Description*:
I noticed a few issues related to go `tool` directive which was introduced [here](https://github.com/envoyproxy/gateway/pull/5304):
1. Go packages which are used only by tools and not directly are not updated by dependabot since they are declared in indirect dependencies block. e.g.:
* github.com/bufbuild/buf
* github.com/golangci/golangci-lint/v2
* github.com/google/go-jsonnet
* sigs.k8s.io/controller-tools
* sigs.k8s.io/kind
* sigs.k8s.io/controller-runtime/tools/setup-envtest
2. Since `sigs.k8s.io/controller-runtime/tools/setup-envtest@v0.0.0-20250217160221-5e8256e05002` consumes `k8s.io/apimachinery v0.33.0-alpha.1` direct apimachinery dependency version was changed from `v0.32.2` to `v0.33.0-alpha.1` in [#5304](https://github.com/envoyproxy/gateway/pull/5304) and since then was updated several times by dependabot with alpha/beta versions(currently `v0.34.0-alpha.0`).
According to `kubebuilder` [docs](https://book.kubebuilder.io/reference/envtest.html) `setup-envtest` should be consumed from s release branch (e.g. [release-0.21](https://github.com/kubernetes-sigs/controller-runtime/tree/release-0.21/tools/setup-envtest)).