tests: add periodic tests that run one service per test

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[gemmahou]

I had something similar months ago(cl) to be able to run fixtures tests by services(and then run multiple services in parallel).

The code looks like(might need revise):

t.Run("fixtures", func(t *testing.T) {
  fixtures := resourcefixture.Load(t)

  groups := sets.NewString()
  for _, fixture := range fixtures {
      groups.Insert(fixture.GVK.Group)
  }

  for _, group := range groups.List() {
      group := group
      groupTestName := strings.TrimSuffix(group, ".cnrm.cloud.google.com")
      t.Run(groupTestName, func(t *testing.T) {
          // t.Parallel()
          for _, fixture := range fixtures {
              if fixture.GVK.Group != group {
                  continue
              }
              runTests(ctx, t, fixture, false)
          }
      })
  }
})

This way, we can use the parameter TestAllInSeries/fixtures/logging to run tests in one service, which would avoid adding an extra environment variable ONLY_TEST_APIGROUP. However, the downside is that we need to always include the service name even when running a single test case, such as TestAllInSeries/fixtures/logging/logginglogmetric.