[Test] Fix failing RBACEngineTests (#126106) (#126183)

Adjusting the test assertion to account for the potential 3rd extra
group (#125900).

Resolves #126061

(cherry picked from commit 7b753d0)

# Conflicts:
#	muted-tests.yml

Author: slobodanadamovic

muted-tests.yml

@@ -488,4 +488,4 @@ tests:
   issue: https://github.com/elastic/elasticsearch/issues/125549
 - class: org.elasticsearch.xpack.application.ModelRegistryUpgradeIT
   method: testUpgradeModels {upgradedNodes=3}
-  issue: https://github.com/elastic/elasticsearch/issues/125535
+  issue: https://github.com/elastic/elasticsearch/issues/125535

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authz/RBACEngineTests.java

@@ -1622,10 +1622,10 @@ public void testGetRoleDescriptorsIntersectionForRemoteClusterHasDeterministicOr
             Set<IndexPrivilege> splitBySelector = IndexPrivilege.resolveBySelectorAccess(
                 Set.copyOf(randomSubsetOf(randomIntBetween(1, 4), IndexPrivilege.names()))
             );
-            // If we end up with failure and data access, we will split and end up with extra groups. Need to account for this for the
-            // final assertion
-            if (splitBySelector.size() == 2) {
-                extraGroups++;
+            // If we end up with failure and data access (or failure, data and failure and data access),
+            // we will split and end up with extra groups. Need to account for this for the final assertion
+            if (splitBySelector.size() >= 2) {
+                extraGroups += splitBySelector.size() - 1;
             }
             for (var privilege : splitBySelector) {
                 remoteIndicesBuilder.addGroup(