fix: don't overflow UI on small screens

[Restioson]

Addresses #1933 partially. This does remove all overflow on small mobile screens that I could find, but it doesn't make it nice necessarily in all cases (see below...)

Unfortunately, there is still one issue which will be harder to resolve:

• When the screen is very small, the position/order list in the trade tab correctly scrolls
• However, the TradingView chart takes up the lion's share of the space, meaning that you are viewing the position/order list through a pinhole, which is very frustrating and hard to see
• The ideal UX solution is to scroll the entire page - not just the position list. This way, the trading view widget will eventually disappear if you scroll down far enough.
• However, this is difficult. We can't just wrap the entire thing in a scroll widget because TabBarView also creates a scroll widget, so it won't work properly. If we remove the scroll widget in TabBarView, it has unconstrained height and refuses to lay itself out. IntrinsicHeight is flat-out disallowed it seems(?). The correct solution is a NestedScrollView, but this is a bit of a pain to implement.

Because it may take a bit longer to fix the trade screen, I've opened this PR in the meantime, as these fixes are separate.

[holzeis]

Can you add before and after screenshots?

Regarding the trading view. How about adjusting its height proportionally to the available space?

[Restioson]

Can you add before and after screenshots?

I can do this

Regarding the trading view. How about adjusting its height proportionally to the available space?

I think that could be a good solution! We can revisit it and make the scroll nice and fancy later if we want.