GraphQL query editor prettify icon lays on top of environment config modal

[devon-wolf]

When editing a GraphQL request, the "prettify" icon button does not render below the environment config modal as expected - it remains visible when the modal is open.

In this screenshot, it renders above the value for the jwt variable:

This may be something I can make a PR for myself, but in case I don't have the time I hope someone can pick it up. It seems like a z-index change would fix it.

Thanks!