[Benchmarks] Revert rig-based R installation in benchmark hooks

[thisisnic]

Describe the bug, including details regarding any error messages, version, and platform.

#49038 switched things up to install from rig but it's not working and I will test locally before making this change; we should revert all of #49038 for now so it at least runs with conda

Component(s)

Benchmarking

[thisisnic]

Closed in #49308