The diff introduces mechanism for setting pendingThread in navInfo while first page load,, so it match `activeChatThreadID` value.
The reason is to load pending thread correctly in navigation after page refresh - when we know only pending thread ID from URL.
The solution doesn't work for sidebars right now. Creating pending sidebar would require addidtional data (like parent thread info) that should be found efficiently using only `sourceMessageID`, and it could be introduced in the future.