feat(Uploader): expose vc-uploader methods: onFileDrop

[XavierLuo]

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[tangjinzhou]

什么场景需要用这个

[XavierLuo]

什么场景需要用这个

用于手动触发 “拖拽上传”

[github-actions[bot]]

This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days

[github-actions[bot]]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.