Mute ml set_upgrade_mode test (elastic#74351)

For elastic#74141

Author: davidkyle

x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/ml/set_upgrade_mode.yml

@@ -158,6 +158,9 @@ teardown:
 
 ---
 "Setting upgrade mode to disabled from enabled":
+  - skip:
+      version: "all"
+      reason: "AwaitsFix https://github.com/elastic/elasticsearch/issues/74141"
   - do:
       ml.start_datafeed:
         datafeed_id: set-upgrade-mode-job-datafeed