feat(layout): 替换导航栏后退图标为自定义图片- 在 index.vue 和 redirect.vue 中将后退图标改为自定义图片

- 保留原有代码并添加注释，以备未来可能的更改

src/layouts/index.vue

@@ -12,7 +12,8 @@
         @click-left="goBack"
       >
         <template #left>
-          <van-icon name="left-long" class-prefix="mobilefont" size="18" style="color: #000" />
+          <img src="@/assets/img/icon_navigate_back.png" class="back-icon" alt="" />
+          <!--          <van-icon name="left-long" class-prefix="mobilefont" size="18" style="color: #000" />-->
         </template>
       </van-nav-bar>
     </header>

src/layouts/redirect.vue

@@ -11,7 +11,8 @@
         @click-left="goBack"
       >
         <template #left>
-          <van-icon name="left-long" class-prefix="mobilefont" size="18" style="color: #000" />
+          <img src="@/assets/img/icon_navigate_back.png" class="back-icon" alt="" />
+          <!--          <van-icon name="left-long" class-prefix="mobilefont" size="18" style="color: #000" />-->
         </template>
         <template #right v-if="$route.meta.shareAction">
           <el-icon