[REF] Move instantiation of Order class to earlier in function

This is part of making the Order object and it's methods available to the non-renewal
form which has the same amount calculation bug the class is used to fix.

Note the Order class is an internal class not the order api which we do wish to switch this
form to using

CRM/Member/Form.php

@@ -63,6 +63,13 @@ class CRM_Member_Form extends CRM_Contribute_Form_AbstractEditPayment {
    */
   public $_priceSet;
 
+  /**
+   * The order being processed.
+   *
+   * @var \CRM_Financial_BAO_Order
+   */
+  protected $order;
+
   /**
    * Explicitly declare the entity api name.
    */
@@ -453,7 +460,13 @@ protected function getPriceSetID(array $params): int {
    * @return array
    */
   protected function setPriceSetParameters(array $formValues): array {
-    $this->_priceSetId = $this->getPriceSetID($formValues);
+    $this->order = new CRM_Financial_BAO_Order();
+    $this->order->setPriceSelectionFromUnfilteredInput($formValues);
+    $this->order->setPriceSetID($this->getPriceSetID($formValues));
+    $this->order->setOverrideTotalAmount($formValues['total_amount']);
+    $this->order->setOverrideFinancialTypeID((int) $formValues['financial_type_id']);
+    // The below will be phased out in favour of the above over time.
+    $this->_priceSetId = $this->order->getPriceSetID();
     $priceSetDetails = $this->getPriceSetDetails($formValues);
     $this->_priceSet = $priceSetDetails[$this->_priceSetId];
     // process price set and get total amount and line items.
@@ -483,16 +496,11 @@ public function testSubmit($formValues) {
    * @throws \CiviCRM_API3_Exception
    */
   protected function getOrderParams(): array {
-    $order = new CRM_Financial_BAO_Order();
-    $order->setPriceSelectionFromUnfilteredInput($this->_params);
-    $order->setPriceSetID($this->getPriceSetID($this->_params));
-    $order->setOverrideTotalAmount($this->_params['total_amount']);
-    $order->setOverrideFinancialTypeID((int) $this->_params['financial_type_id']);
     return [
-      'lineItems' => [$this->_priceSetId => $order->getLineItems()],
+      'lineItems' => [$this->_priceSetId => $this->order->getLineItems()],
       // This is one of those weird & wonderful legacy params we aim to get rid of.
       'processPriceSet' => TRUE,
-      'tax_amount' => $order->getTotalTaxAmount(),
+      'tax_amount' => $this->order->getTotalTaxAmount(),
     ];
   }