Enable data stream lifecycle feature flag in x-pack plugin tests (980…

…50) (elastic#98133)

Added missing feature flag. The reason this used work was that we would
not take into account the value of the feature flag in the usage
response. This changed in
elastic#97442 &
elastic#97425.

Fixes: elastic#98050

x-pack/plugin/build.gradle

@@ -227,6 +227,7 @@ testClusters.configureEach {
 
   requiresFeature 'es.index_mode_feature_flag_registered', Version.fromString("8.0.0")
   requiresFeature 'es.inference_rescorer_feature_flag_enabled', Version.fromString("8.10.0")
+  requiresFeature 'es.dlm_feature_flag_enabled', Version.fromString("8.9.0")
 }
 
 tasks.register('enforceApiSpecsConvention').configure {