Add UR error code when throwing exception from Scheduler::enqueueCommandForCG

[martygrant]

Add UR error code when throwing exception from Scheduler::enqueueCommandForCG.
Remove message string from non adapter specific error exception in checkUrResult as it's only used in the adapter specific error path.

This is related to oneapi-src/unified-runtime#2440 and #18423 where clEnqueueMemFillINTEL was failing with -30 (CL_INVALID_VALUE) but no detail was provided in the log:

terminate called after throwing an instance of 'sycl::_V1::exception'
  what():  Enqueue process failed.
Aborted (core dumped)

This is because the first exception thrown from checkUrResult was being hidden by a second exception thrown from Scheduler::enqueueCommandForCG. I've modified this second exception to include the UR result. The output now looks like:

terminate called after throwing an instance of 'sycl::_V1::exception'
  what():  Enqueue process failed.
Native API failed. Native API returns: 4 (UR_RESULT_ERROR_INVALID_VALUE)