Add another non-standard error code for RP registration

[jhendrixMSFT]

Fixes #19900

[felipebbc]

Hi @jhendrixMSFT

The issue #19900 with the Resource Provider registration has not been resolved by adding the non-standard error code Subscription Not Registered.

The sdk also checks if the response has a 409 error code:

azure-sdk-for-go/sdk/azcore/arm/runtime/policy_register_rp.go

Lines 90 to 92 in 6387cfc

	// getting a 409 is the first indication that the RP might need to be registered, check error response
	if err != nil || resp.StatusCode != http.StatusConflict {
	return resp, err

The error message from the Microsoft.Security/pricings@2022-03-01 call returns a 404 error code, so the provider registration doesn't move forward.

Also, the provider registration requires that the error message contain the provider name in the error.details.target field

azure-sdk-for-go/sdk/azcore/arm/runtime/policy_register_rp.go

Lines 202 to 207 in 6387cfc

	func getProvider(re requestError) (string, error) {
	if len(re.ServiceError.Details) > 0 {
	return re.ServiceError.Details[0].Target, nil
	}
	return "", errors.New("unexpected empty Details")
	}

The error message from the Microsoft.Security/pricings@2022-03-01 does not contain the error.details.target field, it only contains error.code and error.message:

│ PUT https://management.azure.com/subscriptions/[subscription-id]/providers/Microsoft.Security/pricings/VirtualMachines?api-version=2022-03-01
│ --------------------------------------------------------------------------------
│ RESPONSE 404: 404 Not Found
│ ERROR CODE: Subscription Not Registered
│ --------------------------------------------------------------------------------
│ {
│   "error": {
│     "code": "Subscription Not Registered",
│     "message": "Please register to Microsoft.Security in order to view your security status"
│   }
│ }
│ -------------------------------------------------------------------------------- 

I tested out a solution adding the 404 code on line 94 and adding a regex to extract the resource provider name from the error.message. It works but I understand this is not a good solution.

Looking for you to see how we can allow automatic resource provider registration in this scenario.

[jhendrixMSFT]

@felipebbc could you please open a new issue for this so we can track it?