Duplicate browser notifications for chat.expensify.com

[mallenexpensify]

Problem
I'm receiving duplicate browser notifications for new chats on web. I only have chat.expensify.com open (no other expensify.com tabs) so this should be a RN issue.

Solution
We had a similar issue for web, it's here. @marcaaron thinks we likely need to do a similar solution to that, check this PR for details.