Add .ml-stats to the exceptions list

Author: davidkyle

modules/dot-prefix-validation/src/main/java/org/elasticsearch/validation/DotPrefixValidator.java

@@ -68,6 +68,7 @@ public abstract class DotPrefixValidator<RequestType> implements MappedActionFil
             "\\.ml-anomalies-.*",
             "\\.ml-annotations-\\d+",
             "\\.ml-state-\\d+",
+            "\\.ml-stats-\\d+",
             "\\.slo-observability\\.sli-v\\d+.*",
             "\\.slo-observability\\.summary-v\\d+.*",
             "\\.entities\\.v\\d+\\..*",

modules/dot-prefix-validation/src/test/java/org/elasticsearch/validation/DotPrefixValidatorTests.java

@@ -65,7 +65,8 @@ public void testValidation() {
         nonOpV.validateIndices(Set.of(".elastic-connectors-v1"));
         nonOpV.validateIndices(Set.of(".elastic-connectors-sync-jobs-v1"));
         nonOpV.validateIndices(Set.of(".ml-state"));
-        nonOpV.validateIndices(Set.of(".ml-state-001"));
+        nonOpV.validateIndices(Set.of(".ml-state-000001"));
+        nonOpV.validateIndices(Set.of(".ml-stats-000001"));
         nonOpV.validateIndices(Set.of(".ml-anomalies-unrelated"));
 
         // Test ignored patterns