refactor: use constant for sleep delay

[alexandear]

Looks like the sleepDuration constant was introduced but has never been used.

lima/pkg/hostagent/requirements.go

Lines 20 to 24 in 0288a6d

	func (a *HostAgent) waitForRequirements(label string, requirements []requirement) error {
	const (
	retries = 60
	sleepDuration = 10 * time.Second
	)

[AkihiroSuda]

Thanks