[MM-59359] imports/import_validators.go: add openid to auth_service validation (#28082)

server/channels/app/imports/import_validators.go

@@ -320,6 +320,7 @@ var validAuthServices = []string{
 	model.UserAuthServiceLdap,
 	model.ServiceGoogle,
 	model.ServiceOffice365,
+	model.ServiceOpenid,
 }
 
 func validateAuthService(authService *string) *model.AppError {

server/channels/app/imports/import_validators_test.go

@@ -646,6 +646,7 @@ func TestImportValidateUserAuth(t *testing.T) {
 		{model.NewPointer("foo"), model.NewPointer("foo"), false},
 		{nil, model.NewPointer(""), true},
 		{model.NewPointer(""), nil, true},
+		{model.NewPointer(model.ServiceOpenid), model.NewPointer("foo@bar.baz"), true},
 
 		{model.NewPointer("foo"), nil, false},
 		{model.NewPointer("foo"), model.NewPointer(""), false},