Missed scroll in the firefox (when you open issue from timeline)

[ejjjik]

I'm submitting a ...

• bug report
• feature request
• support request => Please do not submit support request here, see note at the top of this template.

What is the current behavior?

When you open the issue with a lot of steps from the timeline page in firefox, scroll is not shown.

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem

1. Open report timeline
2. Open issue contains a lot of steps
3. Try to scroll to the last step

What is the expected behavior?

When you open the issue with a lot of steps from the timeline page in firefox, scroll is shown.

What is the motivation / use case for changing the behavior?

You can not view the test with a large number of steps without reducing the scale of the page in the firefox

Please tell us about your environment:

| Windows | 10 |
| Firefox | 57.0.2 (64-бит) |

Allure version	2.4.1
Test framework	testng@6.13.1
Allure adaptor	allure-testng@2.0-BETA21
Generate report using	allure-maven@2.8

Other information