Unmute SetSingleNodeAllocateStepTests (#122318)

This failing test was already fixed by #121266

Fixes #121495

Author: nielsbauman

muted-tests.yml

@@ -329,9 +329,6 @@ tests:
 - class: org.elasticsearch.ingest.geoip.FullClusterRestartIT
   method: testGeoIpSystemFeaturesMigration {cluster=UPGRADED}
   issue: https://github.com/elastic/elasticsearch/issues/121115
-- class: org.elasticsearch.xpack.core.ilm.SetSingleNodeAllocateStepTests
-  method: testPerformActionSomeShardsOnlyOnNewNodesButNewNodesInvalidAttrs
-  issue: https://github.com/elastic/elasticsearch/issues/121495
 - class: org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
   method: test {p0=search.vectors/42_knn_search_int4_flat/Vector similarity with filter only}
   issue: https://github.com/elastic/elasticsearch/issues/121412