fix: update advection_muscl example to model_eqns=2 (THINC incompatible with model_eqns=3)

THINC/MTHINC only reconstructs partial densities and volume fractions at
faces. For model_eqns=3 (6-equation), the per-fluid internal energies
(eqn_idx%int_en) are left unreconstructed after THINC compression, making
the face states thermodynamically inconsistent. The 5-equation model
(model_eqns=2) has no per-fluid internal energy equations so this
inconsistency cannot occur. Regenerate golden file for test 10DE58AA.

Author: sbryngelson

examples/2D_advection_muscl/case.py

@@ -21,7 +21,7 @@
             "t_step_save": 100,
             # Simulation Algorithm Parameters
             "num_patches": 2,
-            "model_eqns": 3,
+            "model_eqns": 2,
             "alt_soundspeed": "F",
             "num_fluids": 2,
             "mpp_lim": "T",