systemtest: Skip TestTailSampling for now (#7015) (#7016)

Skips the `TestTailSampling` systemtest until elastic/fleet-server#1048
is resolved.

Signed-off-by: Marc Lopez Rubio <marc5.12@outlook.com>
(cherry picked from commit 85b95c3)

systemtest/sampling_test.go

@@ -90,6 +90,8 @@ func TestDropUnsampled(t *testing.T) {
 }
 
 func TestTailSampling(t *testing.T) {
+	// We should remove the skip once the issue is resolved.
+	t.Skip("Skipped due: https://github.com/elastic/fleet-server/issues/1048")
 	systemtest.CleanupElasticsearch(t)
 
 	apmIntegration1 := newAPMIntegration(t, map[string]interface{}{