fix: page doesn't get refreshed when FAST_REFRESH=false

[n3tr]

Page doesn't get refreshed when disabling FAST_REFRESH. This is because the process.env.FAST_REFRESH in webpackHotDevClient is a boolean value, comparing !== 'false' will always return true.

Verify steps

• yarn create-react-app my-app
• yarn start
• Modify App.js content
• The app gets updated through Fast Refresh

FAST_REFRESH=false

• Start the app by using FAST_REFRESH=false yarn start
• Modify App.js
• The app should do a full reload

[ianschmitz]

Great find. Thanks!