feat(ske): Check service enablement only in error case

[Fyusel]

STACKITCLI-287

Description

Checklist

• Issue was linked above
• Code format was applied: make fmt
• Examples were added / adjusted (see e.g. here)
• Docs are up-to-date: make generate-docs (will be checked by CI)
• Unit tests got implemented or updated
• Unit tests are passing: make test (will be checked by CI)
• No linter issues: make lint (will be checked by CI)

[github-actions]

Merging this branch will not change overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/stackitcloud/stackit-cli/internal/cmd/ske/cluster/create	37.84% (ø)
github.com/stackitcloud/stackit-cli/internal/cmd/ske/cluster/list	51.52% (ø)

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Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/stackitcloud/stackit-cli/internal/cmd/ske/cluster/create/create.go	37.84% (ø)	74	28	46
github.com/stackitcloud/stackit-cli/internal/cmd/ske/cluster/list/list.go	51.52% (ø)	66	34	32

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.

[cgoetz-inovex]

it's a bit late, but wouldn't this hide the original error from line 99 (ClusterExists) when service is enabled and the call to ProjectEnabled would return a nil error?
So sth. like

			exists, err := skeUtils.ClusterExists(ctx, apiClient.DefaultAPI, model.ProjectId, model.Region, model.ClusterName)
            // err is now sth. like 'server is down'
			if err != nil {
				// Check if the project is enabled
				enabled, err := serviceEnablementUtils.ProjectEnabled(ctx, serviceEnablementApiClient, model.ProjectId, model.Region)
                 // let's assume call succeeds, enabled=true and err=nil now
				if err != nil {
					return fmt.Errorf("check if project is enabled failed: %w", err)
				}
				if !enabled {
					return &errors.ServiceDisabledError{
						Service: "ske",
					}
				}
				return err
                // we return nil here instead of 'server is down'