MM-45713 - change 500 error to json object (#20682)

* MM-45713 - change 500 error to json object

* validate possible encoding errors and follow standards

* replace normal debugging string with true string

* use bool type instead of string

Co-authored-by: Pablo Velez Vidal <pablo.velez@mattermost.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/cloud.go

@@ -105,6 +105,10 @@ type ValidateBusinessEmailRequest struct {
 	Email string `json:"email"`
 }
 
+type ValidateBusinessEmailResponse struct {
+	IsValid bool `json:"is_valid"`
+}
+
 // CloudCustomerInfo represents editable info of a customer.
 type CloudCustomerInfo struct {
 	Name             string `json:"name"`