Add spector test for SpecialWords_ReservedOperationBodyParams withItems scenario (#3976)

* Initial plan

* feat: add SpecialWords_ReservedOperationBodyParams withItems spector test

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Co-authored-by: v-jiaodi <80496810+v-jiaodi@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: v-jiaodi <80496810+v-jiaodi@users.noreply.github.com>
Co-authored-by: JialinHuang803 <139532647+JialinHuang803@users.noreply.github.com>

Author: 3 people

packages/typespec-ts/test/azureModularIntegration/specialWords.spec.ts

@@ -403,6 +403,12 @@ describe("Special Words Client", () => {
     });
   });
 
+  describe("ReservedOperationBodyParams", () => {
+    it("should post withItems", async () => {
+      await client.reservedOperationBodyParams.withItems(["item"]);
+    });
+  });
+
   describe("ExtensibleStrings", () => {
     it("should put extensible string value", async () => {
       const result =