ksud: don't panic on a broken zip in get_zip_uncompressed_size

[palazik]

get_zip_uncompressed_size iterates the archive with by_index(i).unwrap(). If any entry can't be read the unwrap() panics and the whole ksud process dies.

This is reachable from module install: hand it a truncated or corrupted zip and instead of a clean "failed to read module" error you get a panic.

Since the function already returns Result<u64>, the simple fix is to propagate the error with ?:

let mut total: u64 = 0;
for i in 0..zip.len() {
    total += zip.by_index(i)?.size();
}
Ok(total)

No behavior change for valid archives.