Support Const Propagation for Variables

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**

Currently the SimplifyRule creates its own `ExecutionProps` from the `OptimizerConfig`, rather than this being propogated through correctly. The resulting `ExecutionProps` therefore lacks any `VarProvider` and so const propagation is not possible for variables.

**Describe the solution you'd like**

These variables should be available at optimization time, much like `query_execution_start_time`, to allow for const propagation to work correctly.

**Describe alternatives you've considered**

**Additional context**

#4629 tracks making `ExecutionProps` a trait
#2666 moved `OptimizerRule` away from using `ExecutionProps` in favor of a `OptimizerConfig`

Start by tracing SimplifyRule's creation of ExecutionProps from OptimizerConfig and review how OptimizerRule now receives configuration, along with issues #4629 and #2666. Determine how VarProvider should be available during optimization; done means variables are available at optimization time and const propagation works correctly.

Written by the indexing model from the issue text.