Modify the implementation of the changeUserName method in the api object

frontend/src/API/API.ts

@@ -497,12 +497,28 @@ export const api: API = {
       });
     }
   },
-  changeUserName: function (
-    // eslint-disable-next-line @typescript-eslint/no-unused-vars
-    _data: StrNameChange,
-    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+
+  async changeUserName(
+    data: StrNameChange,
     token: string,
   ): Promise<APIResponse<void>> {
-    throw new Error("Function not implemented.");
+    try {
+      const response = await fetch("/api/changeUserName", {
+        method: "PUT",
+        headers: {
+          "Content-Type": "application/json",
+          Authorization: "Bearer " + token,
+        },
+        body: JSON.stringify(data),
+      });
+
+      if (!response.ok) {
+        return { success: false, message: "Failed to change username" };
+      } else {
+        return { success: true };
+      }
+    } catch (e) {
+      return { success: false, message: "Failed to change username" };
+    }
   },
 };