Fix flakiness of testQueryFiltering due to error bound (#7317) (#7324)

(cherry picked from commit 611e007)

Signed-off-by: Austin Lee <austin.t.lee@gmail.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

server/src/test/java/org/opensearch/search/aggregations/metrics/MedianAbsoluteDeviationAggregatorTests.java

@@ -282,7 +282,7 @@ public static IsCloseToRelative closeToRelative(double expected, double error) {
         }
 
         public static IsCloseToRelative closeToRelative(double expected) {
-            return closeToRelative(expected, 0.1);
+            return closeToRelative(expected, 0.25); // 0.25 = q(1-q) where q = quartile; for median, q = 0.5.
         }
     }