Skip operator privilege action test on release builds (elastic#119386)

The `testEveryActionIsEitherOperatorOnlyOrNonOperator` test has been
reliably muted because release builds frequently miss actions due to
disabled feature flags. There's no straight-forward way to account for
this. This PR changes the test to only run on snapshot builds. This way
we get test coverage while reducing maintenance burden. 

Closes: elastic#118220

Author: n1v0lg

muted-tests.yml

@@ -196,9 +196,6 @@ tests:
 - class: org.elasticsearch.xpack.searchablesnapshots.RetrySearchIntegTests
   method: testSearcherId
   issue: https://github.com/elastic/elasticsearch/issues/118374
-- class: org.elasticsearch.xpack.security.operator.OperatorPrivilegesIT
-  method: testEveryActionIsEitherOperatorOnlyOrNonOperator
-  issue: https://github.com/elastic/elasticsearch/issues/118220
 - class: org.elasticsearch.xpack.esql.action.EsqlActionBreakerIT
   issue: https://github.com/elastic/elasticsearch/issues/118238
 - class: org.elasticsearch.reservedstate.service.FileSettingsServiceTests

x-pack/plugin/security/qa/operator-privileges-tests/src/javaRestTest/java/org/elasticsearch/xpack/security/operator/OperatorPrivilegesIT.java

@@ -6,6 +6,7 @@
  */
 package org.elasticsearch.xpack.security.operator;
 
+import org.elasticsearch.Build;
 import org.elasticsearch.client.Request;
 import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
@@ -165,6 +166,7 @@ public void testServiceAccountUpdateOperatorSettings() throws IOException {
 
     @SuppressWarnings("unchecked")
     public void testEveryActionIsEitherOperatorOnlyOrNonOperator() throws IOException {
+        assumeTrue("Exclude release builds due to maintenance burden around feature flags", Build.current().isSnapshot());
         final String message = "An action should be declared to be either operator-only in ["
             + DefaultOperatorOnlyRegistry.class.getName()
             + "] or non-operator in ["