Contract Message Select/Dropdown UI Improvements

[wottpal]

Our contract has a lot of messages (read & write) with many input parameters, making the contract interaction message selector sometimes a bit hard to use. Two things would improve it IMO:

• I really like that it separates queries/transactions (read-only/write) with an icon but unfortunately we don't really see this very often as it's clipped at the right because the function signature overflows the width. In my opinion it would make sense to split both types of calls into two categories and sort them like that with small sub-headlines.
• It would be nice if the UI component is not only a selector but also an input field which allows for filtering/autocompletion. This way it's much easier to quickly find messages.

Found a inspiration ui here that merges both things I'm describing above (but of course it's only inspirational):