feat: Add metrics for lambda event source mappings (#216)

Author: rrhodes

pkg/cloudWatchConsts/metrics.go

@@ -2021,18 +2021,26 @@ var NamespaceMetricsMap = map[string][]string{
 		"ClaimedAccountConcurrency",
 		"ConcurrentExecutions",
 		"DeadLetterErrors",
+		"DeletedEventCount",
 		"DestinationDeliveryFailures",
+		"DroppedEventCount",
 		"Duration",
 		"Errors",
+		"FailedInvokeEventCount",
+		"FilteredOutEventCount",
 		"Invocations",
+		"InvokedEventCount",
 		"IteratorAge",
 		"OffsetLag",
+		"OnFailureDestinationDeliveredEventCount",
 		"OversizedRecordCount",
+		"PolledEventCount",
 		"PostRuntimeExtensionsDuration",
 		"ProvisionedConcurrencyInvocations",
 		"ProvisionedConcurrencySpilloverInvocations",
 		"ProvisionedConcurrencyUtilization",
 		"ProvisionedConcurrentExecutions",
+		"ProvisionedPollers",
 		"RecursiveInvocationsDropped",
 		"Throttles",
 		"UnreservedConcurrentExecutions",