[MM-43399] Cloud Delinquency Email Sequence (#20814)

* Add DelinquentSince to Subscription fields

* Stashing, migrating

* Adding file

* Adding many email templates

* Fix templates pipeline

* Fix translations

* Fix mocks

* Many changes

* Adjust mocks

* Update i18n/en.json

Co-authored-by: Maria A Nunez <maria.nunez@mattermost.com>

* PR fixes

* Update string

* Update i18n/en.json

Co-authored-by: Maria A Nunez <maria.nunez@mattermost.com>

* Update URL's for buttons to open the delinquency modal

* Update emails from mjml

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Maria A Nunez <maria.nunez@mattermost.com>

api4/cloud.go

@@ -665,6 +665,18 @@ func handleCWSWebhook(c *Context, w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		c.Logger.Info("Updated subscription from webhook event")
+	case model.EventTypeTriggerDelinquencyEmail:
+		var emailToTrigger model.DelinquencyEmail
+		if event.DelinquencyEmail != nil {
+			emailToTrigger = model.DelinquencyEmail(event.DelinquencyEmail.EmailToTrigger)
+		} else {
+			c.Err = model.NewAppError("Api4.handleCWSWebhook", "api.cloud.delinquency_email.missing_email_to_trigger", nil, "", http.StatusInternalServerError)
+			return
+		}
+		if nErr := c.App.SendDelinquencyEmail(emailToTrigger); nErr != nil {
+			c.Err = nErr
+			return
+		}
 
 	default:
 		c.Err = model.NewAppError("Api4.handleCWSWebhook", "api.cloud.cws_webhook_event_missing_error", nil, "", http.StatusNotFound)