Fix AppOps estimation call time out.

AppOps estimation call times out with likely reason being that
when Pooled excutor runs this task when StatsPulAtomService is
not active, mContext.getMainExecutor() provides executor which
is not active.

Test: atest testAppOps
Bug: 143519689
Change-Id: Ie2d61b3304b8cc0beb7d4e0ad06ba58aeed1bb19
1 file changed