Poor distinguishability/contrast in the dark mode contributions widget

[bl4ckswordsman]

There's very poor contrast in the contribution boxes of the dark mode widget in the GitHub for Android app, as seen below:

In the light mode of the widget, the contrast is much better:

Even in the dark mode github.com mobile page, there's much better clarity in the contributions graph, compared to the dark mode widget:

[aconsuegra]

Thanks for your feedback @bl4ckswordsman! I'll create an issue for our engineers so they can look into this.