Fix system property value for inference rescorer tests feature flag (#100366) (#100532)

Author: mark-vieira

test/test-clusters/src/main/java/org/elasticsearch/test/cluster/FeatureFlag.java

@@ -16,7 +16,7 @@
  */
 public enum FeatureFlag {
     TIME_SERIES_MODE("es.index_mode_feature_flag_registered=true", Version.fromString("8.0.0"), null),
-    INFERENCE_RESCORER("es.inference_rescorer_feature_flag_enabled", Version.fromString("8.10.0"), null),
+    INFERENCE_RESCORER("es.inference_rescorer_feature_flag_enabled=true", Version.fromString("8.10.0"), null),
     DATA_STREAM_LIFECYCLE_ENABLED("es.dlm_feature_flag_enabled=true", Version.fromString("8.8.0"), null);
 
     public final String systemProperty;