The first letter avatars should have a unique color per sender, not just per letter

[russelldc]

In Inbox, when two or more emails from different senders with names that had the same first letter, the separation was clear at a glance because of the unique colors.

As it is now, there's one hex color per letter of the English alphabet. So situations like this one are common:

This is definitely nitpicky, but it's something that at least I would like to fix.

I think the solution would involve using a function that hashes the sender's full name and outputs a hex color value. I had a working solution locally, but it spanned the whole spectrum of colors, which is not ideal. The white text needs to be readable, and super vibrant colors don't fit the style of the app.