Fix regression preventing workspace creation

[rainest]

https://github.com/Kong/deck/pull/225/files#diff-2b0546a527b3560f4e7f8501ef7907999b2e1a7f2498a60719630310f7778956R74 attempts to create a workspace with no name, as we only populate it in https://github.com/Kong/deck/pull/225/files#diff-2b0546a527b3560f4e7f8501ef7907999b2e1a7f2498a60719630310f7778956R84-R86

Fix appears to be using wsConfig instead; that works when testing manually.

@mflendrich it looks like this was probably unintentional leftovers from an earlier draft before the commit was pushed. Do you recall if there's any reason we would indeed want to use rootConfig here? Doesn't look like it based on a brief review of the wsConfig population code and go-kong workspace Create(), but to echo Harry's previous comment:

A general node: This part of this codebase has become complex and fragile over time and we should test it. This has never been prioritized as there haven't been many quality issues in this area (yet).

Figured it was worth double-checking as such.

Fix #251

[hbagdi]

@mflendrich You usually have good testing tricks up your sleeve. Is there a way to test this without spinning up a Kong instance and without significant mocking overhead? I might be asking for too much.

Thinking out loud, we should be able to refactor and unit test large parts of this component.
However, that would be a separate task and not part of this PR.
Leaving this comment to have a brief discussion while we are here.

[mflendrich]

without spinning up a Kong instance and without significant mocking overhead?

Without a Kong instance I cannot think of a test here that wouldn't be a "change detector" test.

we should be able to refactor and unit test large parts of this component

For logic (like, translating something to something else) I'm all in for unit tests, however for integrations (like, "action X results in effect Y") I'd opt for tests featuring a real but minimal Kong. What makes it complex is that such a Kong would need to be a part of the test harness, now that we don't have a way to spin up a clean fresh small instance of Kong programmatically.