Code cleanup for toVeloxPlan with ProjectRel

[beliefer]

Description

The current implementation show below have some optimization points.
core::PlanNodePtr SubstraitToVeloxPlanConverter::toVeloxPlan(const ::substrait::ProjectRel& projectRel)

First, reserve more accurate memory for projectNames and expressions.
Second, eliminate the unnecessary colIdx.
Third, using emplace_back and std::move to reduce copy.

Gluten version

main branch