能新增个最大图片数的配置么？

## Current use version？
#### 当前使用的版本是多少？
v3.10.6

有个需求是图片跟视频混合选择
例如最大文件数是12 最大图片数量9 最大视频3
当设置
setMaxSelectNum=12
setMaxVideoSelectNum=3
希望增加个
setMaxImageSelectNum=9

Start by locating the existing setMaxSelectNum and setMaxVideoSelectNum configuration entry points and how mixed image/video selection counts are enforced. Add the corresponding image-count configuration so a total limit of 12 can allow up to 9 images and 3 videos, and verify that the combined and individual limits behave as requested.

Written by the indexing model from the issue text.