feat(transformer): Add split and retain strategy for dedupe (#2761)

test/e2e/conformance/tests/go-wasm-transformer.yaml

@@ -400,6 +400,26 @@ spec:
                 port:
                   number: 8080
 ---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  annotations:
+  name: wasmplugin-transform-request-header-split
+  namespace: higress-conformance-infra
+spec:
+  ingressClassName: higress
+  rules:
+    - host: "foo18.com"
+      http:
+        paths:
+          - pathType: Prefix
+            path: "/"
+            backend:
+              service:
+                name: infra-backend-v1
+                port:
+                  number: 8080
+---
 apiVersion: extensions.higress.io/v1alpha1
 kind: WasmPlugin
 metadata:
@@ -860,4 +880,15 @@ spec:
             headers:
               - key: reroute
                 newValue: true
+    - ingress:
+        - higress-conformance-infra/wasmplugin-transform-request-header-split
+      configDisable: false
+      config:
+        reqRules:
+          - operate: dedupe
+            headers:
+              - key: X-split-dedupe-first
+                strategy: SPLIT_AND_RETAIN_FIRST
+              - key: X-split-dedupe-last
+                strategy: SPLIT_AND_RETAIN_LAST
   url: file:///opt/plugins/wasm-go/extensions/transformer/plugin.wasm