Fix #108198: Particle hair crash when using Hair Dynamics

`hair_out_mesh` and `hair_in_mesh` implicitly share edges.
In `hair_create_input_mesh()`, edge data of `hair_in_mesh` needs to be
updated and therefore are copied to a new location. In the subsequent
frames, `psys->clmd->clothObject->edges` won't be updated and point to
freed memory block. Therefore, Blender crashes.
By freeing `hair_out_mesh` first,
1. in `hair_create_input_mesh(),` at least edge data copying is avoided
2. `psys->clmd->clothObject->edges` always points to correct memory

However, since it's possible that similar situation will happen again
by adding another strong user to the same `CustomData` in the future,
it is safer to update `psys->clmd->clothObject->edges` for every frame.

Pull Request: https://projects.blender.org/blender/blender/pulls/108480

source/blender/blenkernel/intern/cloth.cc

@@ -367,6 +367,10 @@ void clothModifier_do(ClothModifierData *clmd,
     return;
   }
 
+  /* Since implicit sharing is introduced, mesh data can be moved to other places.
+   * Therefore some fields in simulation data need to be updated accordingly */
+  clmd->clothObject->edges = reinterpret_cast<const vec2i *>(mesh->edges().data());
+
   /* try to read from cache */
   bool can_simulate = (framenr == clmd->clothObject->last_frame + 1) &&
                       !(cache->flag & PTCACHE_BAKED);

source/blender/blenkernel/intern/particle_system.c

@@ -3491,12 +3491,14 @@ static void do_hair_dynamics(ParticleSimulationData *sim)
     }
   }
 
-  hair_create_input_mesh(sim, totpoint, totedge, &psys->hair_in_mesh);
-
+  /* Free hair_out_mesh before modifying hair_in_mesh in hair_create_input_mesh() to avoid copying
+   * on write since they share some data */
   if (psys->hair_out_mesh) {
     BKE_id_free(NULL, psys->hair_out_mesh);
   }
 
+  hair_create_input_mesh(sim, totpoint, totedge, &psys->hair_in_mesh);
+
   psys->clmd->point_cache = psys->pointcache;
   /* for hair sim we replace the internal cloth effector weights temporarily
    * to use the particle settings