[TEST] Mute docs snippet test in close-job.asciidoc (#49000)

Due to #48583 (comment)

Author: droberts195

docs/reference/ml/anomaly-detection/apis/close-job.asciidoc

@@ -102,7 +102,7 @@ The following example closes the `total-requests` job:
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 POST _ml/anomaly_detectors/total-requests/_close
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-// TEST[setup:server_metrics_openjob-raw]
+// TEST[skip:sometimes fails due to https://github.com/elastic/elasticsearch/pull/48583#issuecomment-552991325 - on unmuting use setup:server_metrics_openjob-raw]
 
 When the job is closed, you receive the following results: