enable_partitioning set to ForceNew
requires_duplicate_detection set to ForceNew
max_size_in_megabytes would cause a loop if enable_partitioning was true as this
causes the value to be multiplied by 16 for it's effective value, this computed
value is then returned by the ARM API in the same field which caused Terraform
to always detect a change
```
TF_ACC=1 go test ./builtin/providers/azurerm -v -run TestAccAzureRMServiceBusTopic -timeout 120m
=== RUN TestAccAzureRMServiceBusTopic_importBasic
--- PASS: TestAccAzureRMServiceBusTopic_importBasic (345.08s)
=== RUN TestAccAzureRMServiceBusTopic_basic
--- PASS: TestAccAzureRMServiceBusTopic_basic (342.23s)
=== RUN TestAccAzureRMServiceBusTopic_update
--- PASS: TestAccAzureRMServiceBusTopic_update (359.56s)
=== RUN TestAccAzureRMServiceBusTopic_enablePartitioning
--- PASS: TestAccAzureRMServiceBusTopic_enablePartitioning (362.80s)
=== RUN TestAccAzureRMServiceBusTopic_enableDuplicateDetection
--- PASS: TestAccAzureRMServiceBusTopic_enableDuplicateDetection (364.97s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/azurerm 1774.657s
```
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