cli: Fix panic in config get

[xiaolin-ninja]

When running waypoint config get -app=<app> outside the project directory, Waypoint panics instead of returning a proper error.

Now it returns:

❯ waypoint-dev config get -app=example-java
please also define project with -project

[briancain]

👍🏻 Backport too? edit: nevermind, already added!

I do think this could use a changelog though since it fixed a bug