HardcoreHearts (1.14-1.15)

Description:
This skript is a way for your players to be able to have Hardcore Hearts (shown on Hardcore worlds) instead of the normal ones in 1.14.4 (should work well in 1.15). If you don't know what it is, this is how they look like with the default resource pack:

The 1.8 version: https://www.spigotmc.org/resources/hardcore-hearts.66081/
How do I change hearts ?:
To change hearts you need to use the command /hardcore <on/off>
For example if you want to enable hardcore hearts, you must type the command . To go back to normal hearts you must type the command (by default, hardcore hearts are off). If the hearts didn't reload after typing the command, you can use the command to reload them but that shouldn't be necessary.
What can I personalize ?:
You can personalize many things in this skript. For example, you can choose to keep the inventory of the player or not when he reloads his hearts, to heal him or not, to remove his potion effects or not and more!
You can also add a permission if you want the /hardcore command to be exclusive to VIP for instance.
By default, when the player reloads his hearts he keeps the same food level & health, the same inventory and the same potion effects he had before switching hearts and there is no permission on the /hardcore command.
Addons & plugins required:
• Skript (above 2.4 if possible): https://github.com/SkriptLang/Skript/releases
• ProtocolLib (to use packets): https://www.spigotmc.org/resources/protocollib.1997/
• ThatPacketAddon (to use packets): https://forums.skunity.com/resources/thatpacketaddon.847/
• Kosmos (for the WorldType field [packets]): https://forums.skunity.com/resources/kosmos.726/
• Skellett (for respawn and entity ID stuff): https://www.spigotmc.org/resources/skript-java-addon-skellett.34361/
• Skript-Miror (mainly for effects): https://skripttools.net/addons?q=skript-mirror
Disclaimer & Warning:
Switching between normal and Hardcore hearts is not supposed to be a feature in Minecraft (nor in Spigot) that's why I use many packets things and deaths in order to make the clients (your minecraft game) to think this is a hardcore world when it isn't. Due to these workarounds, this skript might be unstable/be weird sometimes, but again some bugs may not be fixable because of the way Minecraft works.
Bug and Help:
I didn't find any bug while testing but if you find some, send me a message on spigot or on Discord (Phe0X#5907) (I won't help you if you leave a 1 star review with a copy paste of a stack of errors)