Use vscode predefined variables for gotests template path

[ValarDragon]

Background

vscode provides default workspace paths! https://code.visualstudio.com/docs/editor/variables-reference

We should be able to remove the manual step of having to edit the vscodes settings to get a working gotests template using these!

Suggested Design

Use correct predefined variable to make gotests template read the correct filepath.

Acceptance Criteria

• [ ] No longer need to edit settings.json manually to get gotests template working

cref @AlpinYukseloglu