Something is definitely wrong with <ThemeProvider>'s typings 👀

## Description

BTW i don't really understand what for this component is needed
Everything seems to work fine even without it

withTheme() HOC kinda provides theming 🤷🏼‍♂️

## Reproducible Demo

I've reproduced this issue on CodeSandbox
Come check that out 👇

[sandbox 🎁](https://codesandbox.io/s/theme-provider-issue-n602nb)

Start with the linked CodeSandbox reproduction and inspect the ThemeProvider typings and usage shown there. Confirm which typing behavior is incorrect and define the expected ThemeProvider usage before changing anything; the issue is done when the reproduction no longer reports the typing problem.

Written by the indexing model from the issue text.