fix: correctly print disk sizes on 32bit systems

[jooola]

The order of when the casting occurs is important, or we might overflow.

The bug can be reproduced with:

GOARCH=386 go test  ./...

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 59.75%. Comparing base (12354bb) to head (4992347).

Files	Patch %	Lines
internal/cmd/server/describe.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #800   +/-   ##
=======================================
  Coverage   59.75%   59.75%           
=======================================
  Files         210      210           
  Lines        7598     7598           
=======================================
  Hits         4540     4540           
  Misses       2419     2419           
  Partials      639      639           

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[jooola]

Found while updating the hcloud alpine package: https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/68362

[jooola]

package main

import (
	"fmt"

	"github.com/dustin/go-humanize"
)

func main() {
	size := int(10)

	fail := uint64(size * humanize.GByte)
	happy := uint64(size) * humanize.GByte

	fmt.Printf("fail: %v\n", fail)
	fmt.Printf("fail: %s\n", humanize.Bytes(fail))

	fmt.Printf("happy: %v\n", happy)
	fmt.Printf("happy: %v\n", humanize.Bytes(happy))
}

$ go run ./main.go
fail: 10000000000
fail: 10 GB
happy: 10000000000
happy: 10 GB

$ GOARCH=386 go run ./main.go
fail: 1410065408
fail: 1.4 GB
happy: 10000000000
happy: 10 GB