Contrast in country flags

Contrast ratio of some locations (Luxembourg, Netherlands, Iceland) blue and background are too small.

Image contrast org.torproject.vpn:id/ivCountryFlag Consider increasing the contrast ratio between this image's foreground and background. The image's contrast ratio is 2.10. This ratio is based on an estimated foreground color of #D72828 and an estimated background color of #003897. Consider increasing this ratio to 3.00 or greater. This item may be only partially visible within a scrollable container.

Image contrast org.torproject.vpn:id/ivCountryFlag Consider increasing the contrast ratio between this image's foreground and background. The image's contrast ratio is 1.97. This ratio is based on an estimated foreground color of #20478B and an estimated background color of #160F43. Consider increasing this ratio to 3.00 or greater.

As usual: move to another milestone (or future) when necessary.