[REF] Minor simplification around assigning taxAmount to the template

Just assign it based on the calculated tax amount for the contribution. If no tax then
just assign that to the tpl. Bye copy & paste

CRM/Member/Form/Membership.php

@@ -1440,9 +1440,6 @@ public function submit(): void {
     // This would always be true as we always add price set id into both
     // quick config & non quick config price sets.
     if (!empty($lineItem[$this->_priceSetId])) {
-      $invoicing = Civi::settings()->get('invoicing');
-      $taxAmount = FALSE;
-      $totalTaxAmount = 0;
       foreach ($lineItem[$this->_priceSetId] as & $priceFieldOp) {
         if (!empty($priceFieldOp['membership_type_id'])) {
           $priceFieldOp['start_date'] = $membershipTypeValues[$priceFieldOp['membership_type_id']]['start_date'] ? CRM_Utils_Date::formatDateOnlyLong($membershipTypeValues[$priceFieldOp['membership_type_id']]['start_date']) : '-';
@@ -1451,12 +1448,8 @@ public function submit(): void {
         else {
           $priceFieldOp['start_date'] = $priceFieldOp['end_date'] = 'N/A';
         }
-        if ($invoicing && isset($priceFieldOp['tax_amount'])) {
-          $taxAmount = TRUE;
-          $totalTaxAmount += $priceFieldOp['tax_amount'];
-        }
       }
-      if ($invoicing) {
+      if (Civi::settings()->get('invoicing')) {
         $dataArray = [];
         foreach ($lineItem[$this->_priceSetId] as $key => $value) {
           if (isset($value['tax_amount']) && isset($value['tax_rate'])) {
@@ -1468,11 +1461,10 @@ public function submit(): void {
             }
           }
         }
-        if ($taxAmount) {
-          $this->assign('totalTaxAmount', $totalTaxAmount);
+
+        $this->assign('totalTaxAmount', $this->order->getTotalTaxAmount());
           // Not sure why would need this on Submit.... unless it's being used when sending mails in which case this is the wrong place
-          $this->assign('taxTerm', $this->getSalesTaxTerm());
-        }
+        $this->assign('taxTerm', $this->getSalesTaxTerm());
         $this->assign('dataArray', $dataArray);
       }
     }