Ensure auto inflate is enabled for Azure Eventhub Namespace

Disabling Auto Inflate for Azure Eventhub Namespace may lead to surge in cost.

In Azure Console -

1. Open the Azure Portal and go to Event Hubs.
2. Select the Event Hubs Namespace you wish to edit.
3. Under Settings, choose Scale.
4. Under Auto-Inflate, check the box for Enable.
5. Set the maximum number as needed.

In Terraform -

1. In the azurerm_eventhub_namespace resource, set auto_inflate_enabled to true.
2. Set the maximum_throughput_units as needed.

References:
https://learn.microsoft.com/en-us/azure/event-hubs/event-hubs-auto-inflate
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/eventhub_namespace#auto_inflate_enabled