Fix custom settings/theme handling for graphql-playground-react

[BrunoScheufler]

This issue pertains to the following package(s):

• GraphQL Playground - Electron App
• GraphQL Playground HTML
• GraphQL Playground
• GraphQL Playground Express Middleware
• GraphQL Playground Hapi Middleware
• GraphQL Playground Koa Middleware
• GraphQL Playground Lambda Middleware

What OS and OS version are you experiencing the issue(s) on?

n/a

What version of graphql-playground(-electron/-middleware) are you experiencing the issue(s) on?

n/a

What is the expected behavior?

n/a

What is the actual behavior?

n/a

What steps may we take to reproduce the behavior?

n/a

Please provide a gif or image of the issue for a quicker response/fix.
n/a

Passing settings & theme props to the graphql-playground currently has no effect, however this is a problem when wanting to utilize anything different from the defaults, for example a light theme which has to be toggled by adding custom settings (and optionally theme) props to the PlaygroundWrapper component. I've been working on a fix which I will submit immediately.