fix(signout): Fixing UI updates after sign out

[arthurdenner]

What kind of change does this PR introduce?
Bug fix. Closes #852.

What is the current behavior?
After signing out, the UI breaks because the UserMenu component is connected to the store and reacts to the user property being updated. (See #852)

What is the new behavior?
Instead of being connected to the store, the UserMenu component receives the user and userMenuOpen props from the Navigation component, which also decides if the UserMenu should render or not based on the user property.

Checklist:

• Documentation
• Tests
• Ready to be merged
• Added myself to contributors table

[CompuIves]

This is really nice @arthurdenner! Thank you so much for building this 😄. Merging it in now!

[arthurdenner]

@CompuIves, sorry for bothering you, but I saw that you reverted this PR and now the sign out is broken again. Also, is there any way to sign in with GitHub during development besides copying the jwt token?

[CompuIves]

Hey! We have to look at this one again, when deploying this one people weren't able to look at their sandbox when signed in (related #894, #893). I completely forgot that UserMenu is used in two places: in the Editor and the other pages. They're a bit different, we need to change the one in Editor as well to make it work.

[arthurdenner]

Sorry, I didn't notice this at all.

[arthurdenner]

@CompuIves, I looked at this problem again and noticed that if we use the isLoggedIn property instead of the user property to compute what to render in the Navigation component, the UI doesn't break (and nothing else needs to be changed).

Can you confirm this?