[jak2/3] Support yakows in custom levels (#3951)

I discovered that `yakow`s are kinda broken if you try to use them in
custom levels in jak 2/3.

It's due to the missing `yakow-lod0` texture and associated fix,
replacing it with `yak-medfur-end`. This solution works fine for the
decompiler on vanilla levels.

But for building custom levels, the requested art-groups were being
handled before the textures were, and so it was impossible to have
`yak-medfur-end` on hand to do the replacement. You'd hit an exception
here because `idx_in_level_texture` would still be `INT32_MAX`:

https://github.com/open-goal/jak-project/blob/c08118509b84feba002bd9e208f49162b4218556/decompiler/level_extractor/extract_merc.cpp#L806

My fix was just to swap the order when building custom levels, and
handle the textures first. I only made the changes for jak2/3, because I
see @Hat-Kid has a slightly different implementation for jak1.

There's one other small change relating to the `combo_id` /
`pc_combo_tex_id` short-circtuiting - I think `pc_combo_tex_id` is
always 0 for vanilla textures? So initially `yakow-lod0` actually ended
up matching the `combo_id` of the checkerboard texture from the
test-zone GLB. I just added another sanity check here that the texture
names match too.

(I also added yakows in the test-zone.jsonc files 🐄)

decompiler/level_extractor/extract_merc.cpp

@@ -729,7 +729,7 @@ s32 find_or_add_texture_to_level(tfrag3::Level& out,
                                  GameVersion version) {
   s32 idx_in_level_texture = INT32_MAX;
   for (s32 i = 0; i < (int)out.textures.size(); i++) {
-    if (out.textures[i].combo_id == pc_combo_tex_id) {
+    if (out.textures[i].combo_id == pc_combo_tex_id && out.textures[i].debug_name == debug_name) {
       idx_in_level_texture = i;
       break;
     }
@@ -746,6 +746,7 @@ s32 find_or_add_texture_to_level(tfrag3::Level& out,
         for (size_t i = 0; i < out.textures.size(); i++) {
           auto& existing = out.textures[i];
           if (existing.debug_name == "yak-medfur-end") {
+            lg::info("found yak-medfur-end to replace missing yakow-lod0");
             idx_in_level_texture = i;
             break;
           }