chore: move templating test to Ginkgo

We let a [go test ](https://github.com/argoproj-labs/gitops-promoter/blob/main/internal/utils/template_test.go)get merged with the template PR feature which means it is not run during the CI steps see [here](https://github.com/argoproj-labs/gitops-promoter/pull/161) for some more details. We should move to Ginkgo 