Mock Lambda test tool is not visible or visible intermittently

**Describe the bug**
Mock Lambda test tool is not visible or visible intermittently as the green executable button

**To Reproduce**
Steps to reproduce the behavior
example:
1. Go to visual studio
2. Load your project
3. Build or not buid the project
4. but your Mock Lambda test tool is not visible

**Expected behavior**
Mock Lambda test tool should be there as per AWS toolkit feature.

**Toolkit Logs**
[log_2025-12-23_08-16-53_17672.txt](https://github.com/user-attachments/files/24302863/log_2025-12-23_08-16-53_17672.txt)

**Development System (please complete the following information):**
- Windows Version: 11 pro
- Visual Studio Version: 2026
- AWS Toolkit for Visual Studio Version: AWS Toolkit with Amazon Q 1.83.0.0

Start by reviewing the attached Toolkit Logs and reproducing the missing or intermittent green Mock Lambda test tool in Visual Studio 2026 with the listed AWS Toolkit version. Compare behavior after loading the project and after building; done means the Mock Lambda test tool is consistently visible when the project is ready.

Written by the indexing model from the issue text.