Navigation buttons hidden on some devices

[cmonfortep]

Background
After clicking on fire button, a bottom dialog appears to request user confirmation to clear all tabs and data.

To reproduce:

• Install app
• Go to settings and switch to light theme (if you're not already on it)
• Go to the browser and press the fire button

Seen on:
Pixel 3 XL device, API 29
Pixel XL emulator, API 29

Actual behavior: Fire dialog appears and however system buttons disappear. See following screenshot:

Expected behavior: Fire dialog appears and system buttons are visible. Example, see how in the following screenshot navigation buttons are visible:

[sm600gg]

Halo me!!!!!

[cmonfortep]

Fix has been merged. Thanks to everyone involved here.