Deadlock in async steps

[xpoft]

Describe the bug

1. WithNewAsyncStep in WithNewAsyncStep will cause deadlock and tests will never finish.

2. WithNewAsyncStep in step won't be executed async

To Reproduce

1. example

package my_suite

import (
	"github.com/ozontech/allure-go/pkg/framework/provider"
)

func (s *Suite) TestSome3(t provider.T) {
	t.Parallel()

	t.WithNewStep("sync-step1", func(sCtx provider.StepCtx) {
		sCtx.WithNewAsyncStep("sync-step1-async-step-1", func(sCtx provider.StepCtx) {
			sCtx.WithNewAsyncStep("sync-step1-async-step-1-step1", func(sCtx provider.StepCtx) {
			})
		})
	})
}

package my_suite

import (
	"time"

	"github.com/ozontech/allure-go/pkg/framework/provider"
)

func (s *Suite) TestSome3(t provider.T) {
	t.Parallel()

	startedAt := time.Now()
	timeSinceStart := func() int64 {
		return int64(time.Since(startedAt).Round(time.Second).Seconds())
	}
	sleepDuration := 5 * time.Second

	t.WithNewStep("sync-step1", func(sCtx provider.StepCtx) {
		sCtx.Logf("sync-step1. start: %d", timeSinceStart())
		time.Sleep(sleepDuration)
		sCtx.Logf("sync-step1. finish: %d", timeSinceStart())

		sCtx.WithNewAsyncStep("sync-step1-async-step-1", func(sCtx provider.StepCtx) {
			sCtx.Logf("sync-step1-async-step-1. start: %d", timeSinceStart())
			time.Sleep(sleepDuration)
			sCtx.Logf("sync-step1-async-step-1. finish: %d", timeSinceStart())
		})
		sCtx.WithNewAsyncStep("sync-step1-async-step-2", func(sCtx provider.StepCtx) {
			sCtx.Logf("sync-step1-async-step-2. start: %d", timeSinceStart())
			time.Sleep(sleepDuration)
			sCtx.Logf("sync-step1-async-step-2. finish: %d", timeSinceStart())
		})
	})

	t.WithNewStep("sync-step2", func(sCtx provider.StepCtx) {
		sCtx.Logf("sync-step2. start: %d", timeSinceStart())
		time.Sleep(sleepDuration)
		sCtx.Logf("sync-step2. finish: %d", timeSinceStart())
	})
}

output

    step_context.go:104: sync-step1. finish: 5
    step_context.go:104: sync-step1-async-step-1. start: 5
    step_context.go:104: sync-step1-async-step-1. finish: 10
    step_context.go:104: sync-step1-async-step-2. start: 10
    step_context.go:104: sync-step1-async-step-2. finish: 15
    step_context.go:104: sync-step2. start: 15
    step_context.go:104: sync-step2. finish: 20

Expected behavior

1. No deadlock
2. Async steps