Expose warp setting graph_conditional in SimulationCfg

[Kotochleb]

This is more of an odd edge case fix.
On a cluster with NVIDIA H100 I had poor performance on Mjlab-Velocity-Flat-Unitree-G1 with 30 s per env step. Turns out setting mujoco_warp.Option.graph_conditional=False solves the issue

When running:

uv run  python scripts/benchmarks/measure_throughput.py \
	--num-envs 4096 \
	--tasks '['"'"'Mjlab-Velocity-Flat-Unitree-G1'"'"']'

I get:

==========================================================================
Task                                 Dec  Physics SPS      Env SPS Overhead
--------------------------------------------------------------------------
Velocity-Flat-G1                       4      108,355        7,776    92.8%

After fixing:

==========================================================================
Task                                 Dec  Physics SPS      Env SPS Overhead
--------------------------------------------------------------------------
Velocity-Flat-G1                       4      451,059      166,072    63.2%

I am well aware this is an edge case as on a different cluster with H100 I am getting absolutely normal performance.