fix: #454

[w568w]

这个 PR 通过修复布局问题解决了 #454：

1. 在非 Flex 容器的子控件上不可使用 Flexible；
2. 用 AutoSizeText 在较小屏幕上自动缩放较长的教师名称列表。

Fixes #454.

[HydrogenC]

2. 用 AutoSizeText 在较小屏幕上自动缩放较长的教师名称列表。

Yeah I've remembered that I introduced thsese code to resolve the problem with very thin screens. But they no longer seem to work with new flutter.

[w568w]

Yeah I've remembered that I introduced thsese code to resolve the problem with very thin screens. But they no longer seem to work with new flutter.

That's weird. I just gave it a try and it's working like a charm.