[Bug]: Uninstall blocked by .Net Runtime dependency

### Description

The .Net Runtime extension dependency is blocking MSSQL uninstall if C# is also installed.

### Steps to Reproduce

1. Install MSSQL extension
2. Install C# extension
3. Uninstall MSSQL

### Affected Area

- [ ] Connection dialog (SQL Server | Azure browse/Fabric browse)
- [ ] Query editor
- [ ] Query results panel
- [ ] Object Explorer
- [ ] GitHub Copilot integration
- [ ] Preview/Edit data
- [ ] Table Designer
- [ ] Schema Designer
- [ ] Schema Compare
- [ ] Local SQL Server Container provisioning
- [ ] SQL database in Fabric provisioning
- [ ] DACPAC/BACPAC export/import
- [ ] SQL Database projects
- [ ] Query Plan Visualizer
- [ ] Other (please describe below)

### If you selected "Other", please describe the affected area

_No response_

### Environment Information

Latest

### Confirmation

- [x] I have searched existing issues and couldn't find a match
- [ ] I want to work on this issue

Reproduce the dependency behavior by installing the MSSQL and C# extensions, then uninstalling MSSQL. Trace the extension dependency handling from the issue's uninstall scenario; done means MSSQL can be removed without the .NET Runtime dependency blocking removal when C# remains installed.

Written by the indexing model from the issue text.