fix(appbar): make allowed children to accept additional props

[brunohkbx]

Comparing a string to child.type.name doesn't work when the component is wrapped by withTheme. So we need to check against its type.

Motivation

#972

Before:

Fixed:

[callstack-bot]

Hey @brunohkbx, thank you for your pull request 🤗. The documentation from this branch can be viewed here. Please remember to update Typescript types if you changed API.

[brunohkbx]

@jaysbytes I should have tested in the example app our last changes, my bad. What do you think?

[awinograd]

I just upgraded from 2.15.2 to 2.16.0 to get the fix for Searchbar nested inside Appbar. I now see this bug (text is black), but only in development. In production, the type check works properly and the colors are as expected (white).

please ignore this for now, sorry! i thought I updated some code but hadn't so this may not be up to date

Update: This does appear to be the case. When I compile with NODE_ENV === production, the text is white and things are fine. In development, the type matching doesn't work as expected. Shall I file a separate issue?