refactor: ticket service mehtods

src/modules/tickets/entities/ticket.entity.ts

@@ -29,7 +29,7 @@ export class Ticket extends BaseEntity {
   danakService: DanakService | null;
 
   @ManyToOne(() => User, (user) => user.tickets, { nullable: true })
-  assignedTo: User;
+  assignedTo: User | null;
 
   @ManyToOne(() => User, (user) => user.tickets, { onDelete: "CASCADE", nullable: false })
   user: User;