PR Request VSIX Build and Upload

@stevedlawrence @mbeckerle How would you guys feel about something like this?

So how I imagine this works is:

- Add another job to the CI
- This job will:
- Build the VSIX file
- Upload to GitHub action as an artifact for the job
- Example of this is at [omega-edit job artifacts](https://github.com/ctc-oss/omega-edit/actions/runs/2922387566)

I believe this would be a nice to have when it comes to checking work of a PR. As this should allow for the checkers to not have to pull down the code and build it themselves, instead they download the VSIX and install it to test. In reality steps would be:

- Download VSIX file from job artifacts
- Uninstall extension (only if installed)
- Install extension via VSIX file, `code --install-extension /FULL/PATH/TO/FILE.vsix`
- Reload VS Code
- Test