Made Trim level Optional (#1937)

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## Bug

- [ ] Related issues linked #1923

apps/client/src/components/citizen/vehicles/modals/register-vehicle-modal.tsx

@@ -258,6 +258,7 @@ export function RegisterVehicleModal({ vehicle, onClose, onCreate, onUpdate }: P
             />
 
             <SelectField
+              isOptional
               label={tVehicle("trimLevels")}
               selectionMode="multiple"
               selectedKeys={values.trimLevels}