[native] Introduce useNativeMessageListData and NativeChatMessageItem

Summary:
On native, we want to include information necessary for ENS resolution in this datatype, since it affects height calculations.

This diff splits the type out from the generic one we have in lib. For now the types are the same, but future diffs will change that.

Test Plan: I created a patch to add a field to NativeChatMessageItem and made sure it worked in Flow

Reviewers: ginsu, atul

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D7163