Enhance notification feed item to display more (3) author names

[nkcmr]

Hi! 👋

The notification's page is a little too brief with displaying the "who" part of a notification, so I thought I would increase it to about 3. The code handles the constant being updated very well, so if it needs to be changed it shouldn't be an issue.

I have tested this by running a local expo frontend just attached to my production account and I looked at my own notifications. My data in production seems to cover all the cases I've considered in my solution.

I think I followed most of the written contributor guidelines, but sorry if I missed something important.

Let me know if I missed anything or if you have any questions! Thanks!