WASB filesystem should not start BandwidthGaugeUpdater if fs.azure.skip.metrics set to true

In Hadoop-11248 we added configuration "fs.azure.skip.metrics". If set to true, we do not register Azure FileSystem metrics with the metrics system. However, BandwidthGaugeUpdater object is still created in AzureNativeFileSystemStore, resulting in unnecessary threads being spawned.

Under heavy load the system could be busy dealing with these threads and GC has to work on removing the thread objects. E.g. When multiple WebHCat clients submitting jobs to WebHCat server, we observed that the WebHCat server spawns ~400 daemon threads, which slows down the server and sometimes cause timeout.