Enable tests that were not being run

[marckhouzam]

What this PR does / why we need it

I noticed that the ginko tests in pkg/config did not have a test suite and therefore were not being run.

Before this PR, notice the [no tests to run].
The test coverage happens because the init() function is automatically run, but nothing is verified, so it is not real test coverage.

$ cd tanzu-cli
~tc
$ g co main
Switched to branch 'main'
Your branch is up to date with 'upstream/main'.
$ go test ./pkg/config -coverprofile coverage.txt
ok  	github.com/vmware-tanzu/tanzu-cli/pkg/config	0.634s	coverage: 12.2% of statements [no tests to run]

With this PR, notice the increased coverage and the fact that it no longer says [no tests to run]:

$ go test ./pkg/config -coverprofile coverage.txt
ok  	github.com/vmware-tanzu/tanzu-cli/pkg/config	1.010s	coverage: 36.7% of statements

Which issue(s) this PR fixes

Fixes # N/A

Describe testing done for PR

Let CI run

Release note

More unit tests

Additional information

Special notes for your reviewer

[anujc25]

Thanks for catching this. 👍