[MM-48088]: Ability to migrate from Monthly to Cloud Pro Annual (#21673)

model/cloud.go

@@ -227,6 +227,7 @@ type CloudWorkspaceOwner struct {
 }
 type SubscriptionChange struct {
 	ProductID string `json:"product_id"`
+	Seats     int    `json:"seats"`
 }
 
 type BoardsLimits struct {