Inbox fetching result handling missing back some cases check

[Gujiawei-Edinburgh]

Inbox fetch stream can be truncated on TRY_LATER or BACK_PRESSURE_REJECTED

In inbox fetch results, beside OK, it can be 'BACK_PRESSURE_REJECTED' and TRY_LATER which are later fetching semantic.

However, under these cases, inbox does not reset the hasMore bit, which will stall the stream prematurely.

[popduke]

Nice catch, PR pls :)