feat: update test message body configuration for Gemini API

src/config/config.rs

@@ -170,7 +170,12 @@ pub static TEST_MESSAGE_BODY: LazyLock<Value> = LazyLock::new(|| {
             }
           ]
         }
-        ]
+      ],
+      "generationConfig": {
+        "thinkingConfig": {
+          "thinkingBudget": 0
+        }
+      }
     })
 });