[VL] Support reading offHeap memory from ResourceProfile

### Description

Stage-level adjustment is already supported https://github.com/apache/incubator-gluten/pull/8209. However, Velox is still [reading the off-heap memory settings from SparkConf](https://github.com/apache/incubator-gluten/blob/f1fc5697d086a5b4a518edba318f44b7c7bf0860/cpp/velox/compute/WholeStageResultIterator.cc#L485). Our team tried increasing the off-heap memory size using ResourceProfile in gluten, but Velox continues to use the earlier value from SparkConf instead of recognizing the updated setting.

### Gluten version

main branch

Start with the ResourceProfile stage-level adjustment described in the issue and inspect WholeStageResultIterator.cc around the linked line where Velox reads off-heap settings from SparkConf. Trace how the updated ResourceProfile value reaches native execution instead of the earlier SparkConf value. Done means Velox uses the ResourceProfile off-heap setting for the affected stage.

Written by the indexing model from the issue text.