Add Build and Test commands for upstream and downstream models

### Describe the feature

Add Build and Test commands for upstream and downstream models in the Parent Models and Children Models panes.

I used dbt Power User for the first time today, and was blown away by the awesome developer experience! Kudos you guys! 👏 🙌 Given how well it worked, I was surprised to see the Build and Test commands for the current/active model but not for the upstream and downstream models.

### Describe alternatives you've considered

It is of course possible to just run the commands in the terminal manually, but how fun is that..?

### Who will benefit?

Everybody using the extension!

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!