* Add worker category as dimension in TaskSlotCountStatsMonitor
* Change description
* Add workerConfig as field
* Modify HttpRemoteTaskRunnerTest to test worker category in taskslot metrics
* Fixing tests
* Fixing alerts
* Adding unit test in SingleTaskBackgroundRunnerTest for task slot metrics APIs
* Resolving false positive spell check
* addressing comments
* throw UnsupportedOperationException for tasklotmetrics APIs in SingleTaskBackgroundRunner
Co-authored-by: Nikhil Navadiya <nnavadiya@twitter.com>