HPCC-8897 Pass cacheHint to use paged cache when querying workunits

Workunit/Dali implements a paged caching mechanism for sorted workunits
and dfu workunit results. To use the caching mechanism, this fix passes
cacheHint as a parameter of getWorkunitSorted() when paging through
workunits/dfu workunits.

Signed-off-by: Kevin Wang <kevin.wang@lexisnexis.com>