cmd/k8s-proxy: use L4 TCPForward instead of L7 HTTP proxy (#18179)

considerable latency was seen when using k8s-proxy with ProxyGroup
in the kubernetes operator. Switching to L4 TCPForward solves this.

Fixes tailscale#18171

Signed-off-by: chaosinthecrd <tom@tmlabs.co.uk>
Co-authored-by: chaosinthecrd <tom@tmlabs.co.uk>

cmd/k8s-operator/depaware.txt

@@ -161,7 +161,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
      💣 github.com/modern-go/reflect2                                from github.com/json-iterator/go
         github.com/munnerz/goautoneg                                 from k8s.io/kube-openapi/pkg/handler3+
         github.com/opencontainers/go-digest                          from github.com/distribution/reference
-        github.com/pires/go-proxyproto                               from tailscale.com/ipn/ipnlocal
+        github.com/pires/go-proxyproto                               from tailscale.com/ipn/ipnlocal+
         github.com/pkg/errors                                        from github.com/evanphx/json-patch/v5+
         github.com/pmezard/go-difflib/difflib                        from k8s.io/apimachinery/pkg/util/diff
    D    github.com/prometheus-community/pro-bing                     from tailscale.com/wgengine/netstack