[C#]: 快速下载优化

[yjl214]

检查项 / Checklist

• 我已在 Issues 页面 中搜索，确认了这一建议未在社区版被提交过 / I have searched the Issues page and confirmed that this suggestion has not been submitted to the Community Edition yet.
• 我确认只是全部选中而没有仔细确认就直接提交了这个 Issue，并且同意这个 Issue 可以直接被关闭 / I confirm that I checked all boxes without carefully reading them, and agree that this issue may be closed directly.
• 我确认我所描述的改进是现实的、有理有据的，而不是我临时起意的 / I confirm that the improvement I describe is realistic, reasonable, and well-justified, rather than something I came up with on a whim.
• 我已知悉社区不对这类 Issue 的完成时间作出任何保证，并有足够的耐心等待社区开发者的处理，同时已知悉如果我作出催促、质问或类似的举动，这个 Issue 可能会被直接关闭 / I understand that the community does not guarantee any completion time for this type of issue, and I am willing to wait patiently for the community developers' review and handling. I also understand that excessive urging, demanding, or similar behavior may result in this issue being closed.

描述 / Description

在 快速下载行为 是 询问并下载到选择的实例 时将 快速下载 的选择菜单优化为多选项

原因 / Reason

这项优化可以让我给多个minecraft实例安装同一模组时更加省时间
如果没有这项优化，我需要多次选择目标实例，比较耗时