Improve glTF logging (#15274)

Also removes all animations but the first one from gltf_frog.gltf
to address the corresponding warning.

Catches some more possible exceptions (out of bounds, optional access)
which might be caused by a broken model to properly log them.

src/unittest/test_irr_gltf_mesh_loader.cpp

@@ -1,6 +1,7 @@
 // Minetest
 // SPDX-License-Identifier: LGPL-2.1-or-later
 
+#include "EDriverTypes.h"
 #include "content/subgames.h"
 #include "filesys.h"