That means you are using a VM. Just for your information, WSL stands for Windows Subsystem for Linux is a feature of Windows that allows the use of a GNU/Linux environment within Windows, that means you can able to use Linux features, terminal, commands in Windows only.
For me the best part of it is you can able to install applications which supports Linux only.
You can change the size of the drive in the vmware host software, then you’ll need to boot the vm from the kali live image to start gparted to expand the drive. You can’t expand the drive if it’s already running.