Add context as second parameter for the mutation function

[asermax]

This PR adds a context that's passed as the second parameter to the mutationFn in a mutation. This change allows access to the mutation's meta (similar to query functions), which I find useful for passing in configurations (similarly as the case mentioned in #7045 (comment)). I've also included the mutationKey in the context, since it came up in a similar discussion #3504.

While this context could eventually include other information, I kept this initial contribution small and simple as to not get all tangled up with all the typing 😅

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Name	Status	Preview	Comments	Updated (UTC)
query	⬜️ Ignored (Inspect)	Visit Preview		Jun 22, 2024 4:07am

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[ATypescriptEnjoyer]

It'd be really cool to get this in 🙏 I use the meta for accessing bearer tokens which works for useQuery but obviously not useMutation

[DavidReinberger]

We'd also really like to get this in, to access ky client in queries/mutations without the workaround mentioned here.

[TkDodo]

I would want to consolidate the efforts in this PR please:

• feat(query-core): add MutationFunctionContext argument to mutateFn #9193