Remove (NEW!) message after logout and update it to be unread count

[HorusGoul]

Fixed Issues

$ #3971

Tests/QA Steps

1. Open two Expensify accounts. Let's call them (a) and (b).
2. Make (a) focus a conversation with an account that is not (b).
3. From (b), send a message to (a).
4. From (a), make sure the title is updated and is set to (1) Expensify.cash, and the favicon has the red dot.
5. From (a), log out and once you're in the Sign In screen, make sure the title and the favicon have been set to their default values, no dot in the favicon, and the Expensify.cash title.

Tested On

• Web
• Mobile Web
• Desktop
• iOS
• Android

Screenshots

Web

Screen.Recording.2021-07-27.at.10.57.59.mov

[deetergp]

Code looks good and tests pass 👍

[OSBotify]

✋ This PR was not deployed to staging yet because QA is ongoing. It will be automatically deployed to staging after the next production release.

[OSBotify]

🚀 Deployed to staging in version: 1.0.80-3🚀

platform	result
🤖 android 🤖	success ✅
🖥 desktop 🖥	success ✅
🍎 iOS 🍎	success ✅
🕸 web 🕸	success ✅

[OSBotify]

🚀 Deployed to production in version: 1.0.81-4🚀

platform	result
🤖 android 🤖	success ✅
🖥 desktop 🖥	success ✅
🍎 iOS 🍎	success ✅
🕸 web 🕸	success ✅