Add DelinquentSince to Subscription fields (#20655)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/cloud.go

@@ -154,6 +154,7 @@ type Subscription struct {
 	LastInvoice     *Invoice `json:"last_invoice"`
 	IsFreeTrial     string   `json:"is_free_trial"`
 	TrialEndAt      int64    `json:"trial_end_at"`
+	DelinquentSince *int64   `json:"delinquent_since"`
 }
 
 // GetWorkSpaceNameFromDNS returns the work space name. For example from test.mattermost.cloud.com, it returns test