Stats: Countries card temporarily appears as a blank white square in dark mode

[thehenrybyrd]

Expected behavior

I expected dark mode to have a dark version of the loading state.

Actual behavior

In dark mode, when scrolling down (for instance in the Days tab) to the Countries card, the map in the card appears white initially. In addition, when tapping "view more" at the bottom of this card, the countries map appears as a white square again before resolving to dark mode.

The same behavior occurs in light mode, but it looks fine. Ideally, the loading state would take dark mode into account and this would be a dark square instead of white.

Steps to reproduce the behavior

1. Be in dark mode
2. Go to Stats > Days/Weeks/Months/Years
3. Scroll down to find the Countries card
4. Note the flash of white
5. Tap "view more" on the Countries card
6. Note again the white loading state

https://user-images.githubusercontent.com/15107387/187869436-71cca841-3895-453d-a6dc-b9aa99e0c2de.mp4

Tested on Samsung Galaxy S21, Android 12, WPAndroid 20.6-rc-2