fix: hide VAT warning during loading and when VAT is valid

Warning no longer flashes during VIES lookup or shows alongside
company info for Belgian B2B (valid VAT but not exempt).

components/checkout/PlanSummary.tsx

@@ -170,7 +170,7 @@ export default function PlanSummary({ plan, interval, limit, country, vatId, onC
               </div>
             </motion.div>
           )}
-          {isVatChecked && vatResult && !vatResult.vat_exempt && (
+          {isVatChecked && !vatLoading && !isVatValid && vatResult && !vatResult.vat_exempt && (
             <motion.p
               initial={{ opacity: 0 }}
               animate={{ opacity: 1 }}