Material-ui: Drawer Elevation doesn't work when paper class is defined

[bhldev]

• [X] This is not a v0.x issue.
• [X] I have searched the issues of this repository and believe that this is not a duplicate.

Expected Behavior 🤔

Drawer with an elevation of 1 has a 1dp elevation for the underlying paper when paper is is defined in classes

Current Behavior 😯

Drawer with an elevation of 1 has no elevation for the underlying paper when paper is is defined in classes

Steps to Reproduce 🕹

Link:

1. https://codesandbox.io/s/8116r7qkr2

Context 🔦

Get the drawer to elevate by 1 dp

Your Environment 🌎

| Tech | Version |
|--------------|---------|
| Material-UI | ^v3.6.1 |
| React | ^v16.6.0 |
| Browser | Chrome 72.0.3626.109 |
| TypeScript | ^3.2.2 |

[oliviertassinari]

@bhldev Have you tried?

<Drawer PaperProps={{ elevation: 10 }}>

[doublejosh]

Paper Props API - https://material-ui.com/api/paper