Publish AWS Serverless Application - region missing

**Describe the bug**

I have used this toolkit for publishing purposes before, but recently, the region I used previously is no longer available in the selection area.
As you can see, the file (aws-lambda-tools-defaults.json) was written with 'cn-northwest-1'.

**To Reproduce**

1. Right Click on 'serverless.template'
2. Click on 'Publish to AWS Lambda'

**Expected behavior**

**Screenshots**

**Toolkit Logs**

**Development System (please complete the following information):**
- Windows Version: Windows 11 25H2
- Visual Studio Version: 17.14.32
- AWS Toolkit for Visual Studio Version: 1.95.0.0

**Additional context**

Start by reproducing the issue from serverless.template using the listed Windows, Visual Studio, and AWS Toolkit versions, then inspect aws-lambda-tools-defaults.json and the toolkit logs. Compare the available publish regions with the configured cn-northwest-1 region; done means the previously configured region is available for selection or the resulting behavior is clearly diagnosed.

Written by the indexing model from the issue text.