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).

首先追蹤 FirebaseOptions 如何初始化 Firebase Cloud Messaging 請求使用的讀取逾時和連線逾時值，並將其與 Google HTTP Client 的預設值進行比較。完成標準是：當 Google 沒有回應時，請求不再無限期掛起，且測試涵蓋所選的預設逾時行為。

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