Days Per Country colors are very similar

**OS & Hardware**
Raspberry Pi with Debian 13 trixie

**Version**
1.14.3

**Describe the bug**
Days per Country insight most countries have almost exactly the same color, so it's very difficult to differentiate

**To Reproduce**
Go to insights, check `Days per Country`

**Expected behavior**
A more diverse color palate would be useful (especially for the most visited countries) , or make it possible to pick a color for each country.

**Screenshots**

**Logs**
N/A

**Additional context**
N/A

Start in the Insights view at the Days per Country visualization and inspect how country colors are assigned. Done means the countries are visibly easier to distinguish, or each country can be assigned a distinct color as proposed; compare the result with the attached screenshot.

Written by the indexing model from the issue text.