Remove unneeded code for detemining resource state

[nghialv]

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

NONE

/cc @nakabonne

[pipecd-bot]

Code coverage for golang is 22.87%. This pull request increases coverage by 0.08%.

File	Function	Base	Head	Diff
pkg/app/piped/cloudprovider/kubernetes/state.go	determineConfigMapHealth	0.00%	0.00%	+0.00%
pkg/app/piped/cloudprovider/kubernetes/state.go	determineSecretHealth	0.00%	0.00%	+0.00%
pkg/app/piped/cloudprovider/kubernetes/state.go	determineServiceAccountHealth	0.00%	0.00%	+0.00%

[nakabonne]

I also thought it's unneeded converting, but it can give us the least amount of validation, by converting to the struct provided by the official API.

[nakabonne]

Because of that, I appended that logic.

[nghialv]

We are converting from the data got from the Kubernetes API.
That data was already validated while applying to the Kubernetes by the Kubernetes API server.
So we don't need that second check.

[nakabonne]

Ah, I was not sure that, now I can approve without hesitation.
/approve

[pipecd-bot]

This pull request is APPROVED by nakabonne.

Approvers can cancel the approval by writing /approve cancel in a comment. Any additional commits also will change this pull request to be not-approved.