Unexpected response when AzureBridge product doesn't exist

When I run Get-AzsAzureBridgeProduct as below, I get an unexpected response error:

```
PS C:\tasks\Azure\azurestack-powershell\src\Azs.AzureBridge.Admin\test> get-AzsAzureBridgeProduct -ActivationName "default" -ResourceGroupName "azurestack-activation" -Name "fakeproduct"

Get-AzsAzureBridgeProduct_Get: Unexpected response retrieving product information.
```

The error should say the resource does not exist, not an "unexpected response".

Start by reproducing the Get-AzsAzureBridgeProduct command shown in the issue with the nonexistent fakeproduct resource, then locate the command's response handling. Confirm the service response for a missing product and update the reported error so it says the resource does not exist; done when the command no longer reports an unexpected response for this case.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.