Add another non-standard error code for RP registration (Azure#20860)

Author: jhendrixMSFT

sdk/azcore/CHANGELOG.md

@@ -19,7 +19,7 @@
 
 ### Bugs Fixed
 * Retry policy always clones the underlying `*http.Request` before invoking the next policy.
-* Added `MissingRegistrationForResourceProvider` to the list of error codes for unregistered resource providers.
+* Added some non-standard error codes to the list of error codes for unregistered resource providers.
 
 ### Other Changes
 

sdk/azcore/arm/runtime/policy_register_rp.go

@@ -175,6 +175,7 @@ func (r *rpRegistrationPolicy) Do(req *azpolicy.Request) (*http.Response, error)
 var unregisteredRPCodes = []string{
 	"MissingSubscriptionRegistration",
 	"MissingRegistrationForResourceProvider",
+	"Subscription Not Registered",
 }
 
 func isUnregisteredRPCode(errorCode string) bool {

sdk/azcore/arm/runtime/policy_register_rp_test.go

@@ -412,6 +412,11 @@ func TestRPRegistrationPolicyEnvironmentsInSubExceeded(t *testing.T) {
 	require.EqualValues(t, 0, logEntries)
 }
 
+func TestIsUnregisteredRPCode(t *testing.T) {
+	require.True(t, isUnregisteredRPCode("Subscription Not Registered"))
+	require.False(t, isUnregisteredRPCode("Your subscription isn't registered"))
+}
+
 type fakeClient struct {
 	ep string
 	pl runtime.Pipeline