Remove enabledFeatures from the store.

[nicosampler]

@mikheevm:

It can be computed only with a version number, doesn't have to be stored.

const featuresEnabled = useMemo(() => enabledFeatures(safe.version), [safe.version])

literally, that's it, except for removing the calculation in fetchSafe.ts, updating types, and replacing 2 references to the selector with a function from above.

Following the discussion initiated here: https://github.com/gnosis/safe-react/pull/1477/files#r505509294