[chatapp-mobile] duplicate message date key in ChatRoomScreen.js

[finbertmds]

Describe the bug
In mobile, at ChatRoomScreen, load more message, appear warning message duplicate key flatlist.
Branch: develop.
Commit: 4adcbe9

To Reproduce
Steps to reproduce the behavior:

1. Go to 'ChatRoomScreen'
2. Scroll up to load more old messages
3. Send message from other device to this room
4. One more time scroll up to load more old messages
5. See error

Expected behavior
Not show warning message. Find reason. Displayed message is been duplicate?

Screenshots
https://prntscr.com/vnn4vj
https://prntscr.com/vnn44k

Smartphone (please complete the following information):

• Device: Simulator iPhone11
• OS: iOS13.2.2
• App: chatapp