Fix DataTiersUsageTransportActionTests testCalculateMAD (#64596) (#64629)

Random the compression factor starting with 1 (to elimitinate nearly 0 values)
which will only use one centroid (and yield 0 for MAD as the aproximate median
is the same as the single centroid mean value)

(cherry picked from commit 940e0f1)
Signed-off-by: Andrei Dan <[email protected]>

Co-authored-by: Elastic Machine <[email protected]>

Author: andreidan

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/DataTiersFeatureSetTests.java

@@ -29,7 +29,7 @@ public class DataTiersFeatureSetTests extends ESTestCase {
     public void testCalculateMAD() {
         assertThat(DataTiersFeatureSet.computeMedianAbsoluteDeviation(new TDigestState(10)), equalTo(0L));
 
-        TDigestState sketch = new TDigestState(randomDoubleBetween(0, 1000, false));
+        TDigestState sketch = new TDigestState(randomDoubleBetween(1, 1000, false));
         sketch.add(1);
         sketch.add(1);
         sketch.add(2);