Add static check to ensure plugin implements PrepareDataPlugin interface

Author: rahulgurnani

pkg/epp/scheduling/framework/plugins/multi/prefix/plugin_test.go

@@ -30,9 +30,13 @@ import (
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/backend"
 	backendmetrics "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/backend/metrics"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/plugins"
+	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/requestcontrol"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/scheduling/types"
 )
 
+// static check to ensure Plugin implements the PrepareDataPlugin interface.
+var _ requestcontrol.PrepareDataPlugin = &Plugin{}
+
 func TestPrefixPluginCompletion(t *testing.T) {
 	config := Config{
 		BlockSize:              4,