Happy & Top Notch Toddler Fix (+ Top Notch Infant Thumbnail fix that nobody ever asked for)

Attention:
There's currently a bug in this mod which will cause random sims to travel with you, when you travel to another lot. They will leave immediately after, without interacting with your sim and there seems to be no further consequences from this bug, however it can be quite irritating. I honestly have no idea why this bug occurs, as it mostly affects premade sims that have never even been toddlers or gained a toddler skill in the first place.
I was working on a do-over, but I just can't get a clean injection working without it causing other bugs. So for now I'm stuck without external help.


I guess if you looked for this, you know what it's about.

There's this bug for about 18 months now where the reward traits "Happy Toddler" and "Top Notch Toddler" are unobtainable. For me, it made generational gameplay or raising toddlers in general super frustrating, since there's no reward in leveling toddler skills (apart from starting child skills 1-2 levels higher). Of course you can still cheat the traits, but it's just not the same.

I've heard there's apparently already a fix out there, but I couldn't find it, so I made one myself.

Installation & Requirements
As usual, put the .package files into your Mods folder or subfolders. The .ts4script however needs to be in the mod folder itself or a direct subfolder at max. This mod requires XML Injector.

What's causing the bug?
Once your toddler skills are at the required levels, you should receive a hidden trait called "trait_Happy_Toddler_Hidden" (or "trait_Top_Notch_Toddler_Hidden"), which will turn into the regular, visible variant once you age up to child. But for some reason, the hidden trait is never granted in the first place.

How does this mod work?
Everytime you level a toddler skill to 3 or higher, my mod will check if they're all above 3 and if so, your sim will be granted the hidden "Happy Toddler" trait. Additionally, if you're leveling a toddler skill to 5 (or potty to 3), my mod will also check if they're all at 5 and if so, you will be granted the hidden "Top Notch Toddler" trait, while the hidden "Happy Toddler" trait will be removed.

Optional: Top Notch Infant thumbnail fix
There's also a tiny, little bug with the Top Notch Infant trait - it is using the thumbnail of the Top Notch Toddler trait. The Happy Infant trait however has it's own thumbnail. By chance, I recently found the actual Top Notch Infant thumbnail in the gamefiles, is it the Happy Infant thumbnail inside a star. So I spent more time than I wanna admit, trying to understand any of the Tuning tutorials and fixing it for myself, since apparently... nobody ever noticed this before? Anyways, that's what started this mod.
If you disagree with me here and you think the Top Notch Infant thumbnail is perfectly fine as is, then you can just delete the thumbnail fix package file after unzipping.
(Also I have no idea if my override will mess up any text strings and will need translations, so please let me know.)

Disclaimer
I know there's a more elegant way to fix this. Both traits got their own hidden aspiration and one could figure out why they don't work. Maybe I will later on. But for now I'm satisfied with the outcome, since this is my first mod ever, so I wanted to share it.

Credits
Sims 4 Studio
The Sims 4 Mod Constructor by Zerbu