fix/rerenders: useMemo to avoid unnecessary rerenders

[stavros-liaskos]

• All new/changed/fixed functionality is covered by tests N/A
• I have added documentation for all new/changed functionality N/A

📋 Changes

useContext is triggering unnecessary re-renders. With useMemo this can be avoided as described here.

tl;tr
I noticed this when I integrated why-did-you-render to release-raccoon. Atm it is using 2 contexts, I implemented the above fix to ThemeProvider and this PR takes care of fixing this in useUser too.

📎 References

• Related issue from other repository: https://github.com/stavros-liaskos/release-raccoon/pull/20/files#r1041055599

🎯 Testing

Clicking on the Home btn calls the hook again but returns same results different objects that are equal by value.

[vercel]

@stavros-liaskos is attempting to deploy a commit to the Auth0 Team on Vercel.

A member of the Team first needs to authorize it.

[adamjmcgrath]

Thanks for your contribution @stavros-liaskos!

Could you remove why-did-you-render and add a regression test to the SDK similar to https://github.com/auth0/auth0-react/pull/318/files#diff-50f0ae9241a4ab6bc7b4c79924a45f52f654e4a03ad982942b68e0142a287877

[adamjmcgrath]

Thanks @stavros-liaskos

The base branch was changed.

[stavros-liaskos]

Thanks @stavros-liaskos

Thank you @adamjmcgrath