Fix #105715: Freeing the edit-mesh causes future access to fail

The BPyBMesh in `BMesh::py_handle` was invalidated but not cleared,
causing future access to return a 'dead' bmesh.

source/blender/python/bmesh/bmesh_py_types.c

@@ -989,7 +989,11 @@ static PyObject *bpy_bmesh_free(BPy_BMesh *self)
 
     bm_dealloc_editmode_warn(self);
 
-    if ((self->flag & BPY_BMFLAG_IS_WRAPPED) == 0) {
+    if (self->flag & BPY_BMFLAG_IS_WRAPPED) {
+      /* Ensure further access doesn't return this invalid object, see: #105715. */
+      bm->py_handle = NULL;
+    }
+    else {
       BM_mesh_free(bm);
     }