fix(investment): 修复投资学习页面链接路径

- 将链接路径从 $vo.url 修改为 $vo.main_content.resource_download.0.url
- 确保资源下载链接正确显示
- 修复了英文版投资页面的链接逻辑
- 修复了中文版投资页面的链接逻辑

public/themes/website/1/en/demo/investment.html

@@ -195,7 +195,7 @@
       <div class="iv-learn__body">
         <ul class="iv-learn__list">
           {hcTaglib:contentPage cid="$ui_invest_learn" mainField="*" subField="*"  name="hc_content" limit="12" item="vo"}
-          <a class="iv-learn__item" href="{$vo.url ?? ''}" target="_blank">
+          <a class="iv-learn__item" href="{$vo.main_content.resource_download ? $vo.main_content.resource_download.0.url : ''}" target="_blank">
             <time class="iv-learn__date" datetime="{$vo.publish_time|date='Y-m-d'}">{$vo.publish_time|date='Y-m-d'}</time>
             <h3 class="iv-learn__name">{$vo.title}</h3>
             <span class="iv-learn__link">

public/themes/website/1/zh/demo/investment.html

@@ -195,7 +195,7 @@
       <div class="iv-learn__body">
         <ul class="iv-learn__list">
           {hcTaglib:contentPage cid="$ui_invest_learn" mainField="*" subField="*"  name="hc_content" limit="12" item="vo"}
-          <a class="iv-learn__item" href="{$vo.url ?? ''}" target="_blank">
+          <a class="iv-learn__item" href="{$vo.main_content.resource_download ? $vo.main_content.resource_download.0.url : ''}" target="_blank">
             <time class="iv-learn__date" datetime="{$vo.publish_time|date='Y-m-d'}">{$vo.publish_time|date='Y-m-d'}</time>
             <h3 class="iv-learn__name">{$vo.title}</h3>
             <span class="iv-learn__link">