An item with the same key has already been added

2020-09-17 13:05:47.4165|Info|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|Executing job step IndexBIQMetrics(85)
2020-09-17 13:05:47.4165|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|IndexBIQMetrics(85): Starting
2020-09-17 13:05:47.4165|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|LicensedReports.EntityMetrics=True
2020-09-17 13:05:47.4165|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|Input.Metrics=True
2020-09-17 13:05:47.4165|Warn|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|No BIQ targets to process
2020-09-17 13:05:47.4165|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|IndexBIQMetrics(85): total duration 00:00:00.0015382 (1 ms)
2020-09-17 13:05:47.4310|Info|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|Executing job step IndexAPMMetricsList(86)
2020-09-17 13:05:47.5366|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|IndexAPMMetricsList(86): Starting
2020-09-17 13:05:47.5366|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|LicensedReports.EntityMetrics=True
2020-09-17 13:05:47.5366|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|Input.MetricsList=True
2020-09-17 13:05:47.5366|Info|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|IndexAPMMetricsList(86): [1/394], https://discoverfinancial.saas.appdynamics.com APPNAME(xxx) [APM]
2020-09-17 13:05:47.8322|Warn|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|System.ArgumentException: An item with the same key has already been added. Key: Oracle DB-LDAP-Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior)
at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](List`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector)
at AppDynamics.Dexter.ProcessingSteps.IndexAPMMetricsList.Execute(ProgramOptions programOptions, JobConfiguration jobConfiguration) in C:\appdynamics\AppDynamics.DEXTER\src\ProcessingSteps\Index\IndexAPMMetricsList.cs:line 110
2020-09-17 13:05:47.8414|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|IndexAPMMetricsList(86): [1/394], https://discoverfinancial.saas.appdynamics.com Account_Center_Decision_Engine duration 00:00:00.3027369 (302 ms)
2020-09-17 13:05:47.8414|Trace|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|IndexAPMMetricsList(86): total duration 00:00:00.3167905 (316 ms)
2020-09-17 13:05:47.8542|Warn|AppDynamics.Dexter|8500|1|AppDynamics.Dexter.Console|If you need support, please review https://github.com/Appdynamics/AppDynamics.DEXTER/wiki#getting-support and send the logs

Start at src/ProcessingSteps/Index/IndexAPMMetricsList.cs line 110 and inspect the ToDictionary call associated with the duplicate Oracle DB key in the log. Reproduce the failure using the reported APM metrics input, then determine the expected behavior for duplicate keys and verify that this case no longer raises the reported exception.

Written by the indexing model from the issue text.