* [PM-17562] Add Azure Service Bus support for event integration retries
* Cleanup AzureServiceBusIntegrationListenerService.cs; add nullable
* Removed IntegrationHandlerBase* since it is no longer used (We removed the subclasses previously)
* Changed strategy to assume ApplyRetry always gives us a non-null DelayUntilDate; Added test to confirm as well
* Renamed ProductType to ProductTierType
* Renamed Product properties to ProductTier
* Moved ProductTierType to Bit.Core.Billing.Enums namespace from Bit.Core.Enums
* Moved PlanType enum to Bit.Core.Billing.Enums
* Moved StaticStore to Bit.Core.Billing.Models.StaticStore namespace
* Added ProductType enum
* dotnet format