`CamelCasedPropertiesDeep`/`SnakeCasedPropertiesDeep` breaks `unknown` values

[guansss]

Bug description

import type {CamelCasedPropertiesDeep,SnakeCasedPropertiesDeep} from 'type-fest';

type Foo = {
	x: unknown;
};

type CamelCased = CamelCasedPropertiesDeep<Foo>;
type SnakeCased = SnakeCasedPropertiesDeep<Foo>;

Expected:

type CamelCased = {
	x: unknown;
};
type SnakeCased = {
	x: unknown;
};

Actual:

type CamelCased = {
	x: {};
};
type SnakeCased = {
	x: {};
};

Repro

https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBDAnmApnA3gYQIYhQGxwGcUATABSglVmBSIBEUUwAaAZQDtsBrFYspWopa9JiwC+cAGZUQcAORJUAWmn0YCgNwBYAFD7laAGIQIcALwZ9ASAAeALjgBXTj04QA7p116Jvw2Q0HDxCbBJSSzgQggEKKhoYOkZmMAAeUwgAPl84PLgAegK4AD0Afn1A1DguXn5wsijavjihROTxdMyc-XzC4vL9IA