Fix undefined variable error in modTemplateVar (#16427)

Move $policyTable variable up in scope to avoid error that occurs when $rgEnabled (~L993) is false and $catEnabled (~L1019) is true.

Co-authored-by: Jim Graham <info@sparkmediagroup.com>

core/model/modx/modtemplatevar.class.php

@@ -990,9 +990,9 @@ public function findPolicy($context = '') {
         $enabled = ($catEnabled || $rgEnabled);
         if ($enabled) {
             if (empty($this->_policies) || !isset($this->_policies[$context])) {
+                $policyTable = $this->xpdo->getTableName('modAccessPolicy');
                 if ($rgEnabled) {
                     $accessTable = $this->xpdo->getTableName('modAccessResourceGroup');
-                    $policyTable = $this->xpdo->getTableName('modAccessPolicy');
                     $resourceGroupTable = $this->xpdo->getTableName('modTemplateVarResourceGroup');
                     $sql = "SELECT Acl.target, Acl.principal, Acl.authority, Acl.policy, Policy.data FROM {$accessTable} Acl " .
                             "LEFT JOIN {$policyTable} Policy ON Policy.id = Acl.policy " .