Not meaningful timeout default values leading to hanging requests

### [REQUIRED] Step 2: Describe your environment

* Operating System version: MacOS Sonoma 14.1.1
* Firebase SDK version: v9.2.0
* Library version: _____
* Firebase Product: Firebase Cloud Messaging

### [REQUIRED] Step 3: Describe the problem
Sometimes the Google Server do not respond (like described in #850 ). However, the default values to read timeout and connect timeout are "0" because they are default initialized with 0 in the FirebaseOptions. So these requests hang for infinite time.

#### Steps to reproduce:
Send a message via FCM and the SDK. If Google does not respond, there is not timeout.

#### Fix:
Provide meaningful default values like 20s. This is the default in the Google HTTP Client (com.google.api.client.http.HttpRequest#readTimeout).

首先跟踪 FirebaseOptions 如何初始化 Firebase Cloud Messaging 请求使用的读取超时和连接超时值，并将其与 Google HTTP Client 的默认值进行比较。完成标准是：当 Google 不响应时，请求不再无限期挂起，并且测试覆盖所选的默认超时行为。

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