[charts] Add Initializable type and behaviour to allow checking if a complex context has been initialized.

[JCQuintas]

• Add Initializable<T> type
• Make sure complex user-facing contexts are initializable so we can more consistently check if they are actually present in the scope.
• Make sure simple user-facing contexts are initializable (useSvgRef)
• Add tests to ensure the checks
• Use hooks in place of useContext

Reference

Contexts are never undefined, they always have their default values, so the previous checks were doing nothing.

For contexts where the type is allow null|undefined but is required to be non-null at runtime, we can just check for thuthness

[mui-bot]

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[romgrk]

Not sure how much it applies here, but in the grid I've been removing a lot of spread operator usages due to their cost. If there is a way to avoid it here, it might be nice to do it. E.g. split the boolean flag and the data as { isInitialized: boolean, data: T }.

[alexfauquette]

I don't see reason of not doing this split between the data and the isInitialized. Since only hooks are user-facing, we can add the data in context and return the data when using the hook.

[JCQuintas]

I had it ready, I just spent a lot of time trying to understand why the karma tests are failing when using the ErrorBoundary. It seems it is an issue with our karma setup here: https://github.com/mui/material-ui/blob/next/packages-internal/test-utils/src/setupKarma.js
and also possibly that we override the console somewhere I couldn't find. But in the end I couldn't find a proper solution to it, so I just skip it in karma 😓

[JCQuintas]

Thanks for the input btw

[alexfauquette]

Outside of the romgrk comments, that looks nice 👍