Type error: wp_cache_delete can return null

[nymwo]

Due to this method returning bool|null: https://github.com/litespeedtech/lscache_wp/blob/ae7624ebd11fd4b832987a7c1a0779e5488f078c/src/object-cache.cls.php#L740-L749

wp_cache_delete returns bool|null even though it's documented as returning bool: https://github.com/litespeedtech/lscache_wp/blob/ae7624ebd11fd4b832987a7c1a0779e5488f078c/src/object.lib.php#L202-L212