derp/derphttp: remove ban on websockets dependency

The event bus's debug page uses websockets.

Updates #15160

Signed-off-by: David Anderson <dave@tailscale.com>

derp/derphttp/derphttp_test.go

@@ -17,9 +17,7 @@ import (
 
 	"tailscale.com/derp"
 	"tailscale.com/net/netmon"
-	"tailscale.com/tstest/deptest"
 	"tailscale.com/types/key"
-	"tailscale.com/util/set"
 )
 
 func TestSendRecv(t *testing.T) {
@@ -487,23 +485,3 @@ func TestProbe(t *testing.T) {
 		}
 	}
 }
-
-func TestDeps(t *testing.T) {
-	deptest.DepChecker{
-		GOOS:   "darwin",
-		GOARCH: "arm64",
-		BadDeps: map[string]string{
-			"github.com/coder/websocket": "shouldn't link websockets except on js/wasm",
-		},
-	}.Check(t)
-
-	deptest.DepChecker{
-		GOOS:   "darwin",
-		GOARCH: "arm64",
-		Tags:   "ts_debug_websockets",
-		WantDeps: set.Of(
-			"github.com/coder/websocket",
-		),
-	}.Check(t)
-
-}