[lib] Include the rawChatName when constructing the chat mention search index

Summary:
This diff is the final one in the stack. It allows us to actually @-mention a chat with ENS users with a cleared name by the member's wallet addresses. This is done in the same way we construct our search indexes for users - we take all possible search terms into an array for the thread ID and then join them by a space. For reference, here is the code for the user search index.

Part of ENG-5436

Depends on D10460

Test Plan:
Please see the videos below where I can now @-mention the chat both by ENS name and wallet addresses.

Reviewers: atul, ginsu, inka

Reviewed By: inka

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D10461