Add third bubble color for non-E2E
Since the original goal for the default messaging app was to have SMS and always-E2E IM messages, the design of the bubbles was done with that in mind (green = insecure SMS, blue = secure IM).
In reality we now have a lot more cases than that though, and I think the bubble colors ought to reflect that. Currently blue is used for both E2E and non-E2E messages, which could give people a false sense of security. I think we should introduce a new color for non-E2E messages (which aren't SMS) to clear this up. To start with I'd try a neutral gray (e.g. #eeeeee), but we can iterate on that.
Then we'd have
- Green - SMS
- Gray - Non-E2E IM conversation
- Blue - E2E IM conversaion