**Backport:** https://codeberg.org/forgejo/forgejo/pulls/9252
Bring the code in line with the documentation that claims the `[quota.default].TOTAL` option supports unit suffixes.
Resolvesforgejo/forgejo#8996
Co-authored-by: Brook <brook@noreply.codeberg.org>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/9263
Co-authored-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>
Co-committed-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>