message: fix FlexItem lint errors
diff: import React from 'react'
  import FlexItem from '../FlexItem'
  import {FLEX_ITEM} from '../system-props'
  -import theme from '../theme'
  -import {render, renderStyles} from '../utils/testing'
  +import {render} from '../utils/testing'
  describe('FlexItem', () => {
  it('is a system component', () => {
  