[lib] Update useResolvedThreadInfosObj return type

Summary: One of the changes from https://gist.github.com/Ashoat/efa03bb380aa602abe2499770b9ddfbd. Separating into separate diff because the other change caused some cascading `flow` issues in `native`... which I'll address in separate diff.

Test Plan: flow

Reviewers: ashoat

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D9935

lib/utils/entity-helpers.js

@@ -93,7 +93,7 @@ function useResolvedOptionalThreadInfos(
 function useResolvedThreadInfosObj(
   threadInfosObj: { +[id: string]: ThreadInfo },
   options?: ?UseENSNamesOptions,
-): { +[id: string]: ResolvedThreadInfo } {
+): { +[id: string]: ResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo } {
   const threadInfosArray = React.useMemo(
     () => values(threadInfosObj),
     [threadInfosObj],