Fix ADRealmTests in FIPS 140 JVMs (elastic#47437)

The changes introduced in elastic#47179 made it so that we could try to
build an SSLContext with verification mode set to None, which is
not allowed in FIPS 140 JVMs. This commit address that

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authc/ldap/ActiveDirectoryRealmTests.java

@@ -533,12 +533,12 @@ private Settings settings(RealmConfig.RealmIdentifier realmIdentifier, Settings
                 .put(getFullSettingKey(realmIdentifier.getName(), ActiveDirectorySessionFactorySettings.AD_DOMAIN_NAME_SETTING),
                         "ad.test.elasticsearch.com")
                 .put(getFullSettingKey(realmIdentifier, DnRoleMapperSettings.USE_UNMAPPED_GROUPS_AS_ROLES_SETTING), true);
-        if (randomBoolean()) {
+        if (inFipsJvm()) {
             builder.put(getFullSettingKey(realmIdentifier, SSLConfigurationSettings.VERIFICATION_MODE_SETTING_REALM),
                     VerificationMode.CERTIFICATE);
         } else {
             builder.put(getFullSettingKey(realmIdentifier, SSLConfigurationSettings.VERIFICATION_MODE_SETTING_REALM),
-                    VerificationMode.NONE);
+                    randomBoolean() ? VerificationMode.CERTIFICATE : VerificationMode.NONE);
         }
         return builder.put(extraSettings).build();
     }