Fix RandomSamplerIT#testRandomSamplerHistogram test input (elastic#88191

) (elastic#88288)

Periodically, a single 10 value is included which causes a 3rd histogram bucket to be created with very few values. Meaning sampling wouldn't get any docs that hit that bucket (especially with the randomly included deleted docs).

The failures that I saw had the 10.0 bucket with just one document.

closes: elastic#88108

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/bucket/RandomSamplerIT.java

@@ -54,7 +54,7 @@ public void setupSuiteScopeCluster() throws Exception {
                 randomNumber = randomDoubleBetween(0.0, 3.0, false);
             } else {
                 keywordValue = UPPER_KEYWORD;
-                randomNumber = randomDoubleBetween(5.0, 10.0, false);
+                randomNumber = randomDoubleBetween(5.0, 9.0, false);
             }
             builders.add(
                 client().prepareIndex("idx")