TabContainer Overflow: Incorrect Scrolling

[MarcusNotheis]

Describe the bug
A clear and concise description of what the bug is.

The Text Only Tab Container has an incorrect scrolling behaviour in the overflow mode.
If you click on the right icon the container scrolls to the right.
If you click in the left icon, the container scrolls to the right too.

This is only happening for the Text Only mode, in the Basic TabContainer example it is working as expected.

I could reproduce this error in my local project too, so I would guess it is more a issue with the component itself than with the playground.

To reproduce
Steps to reproduce the behavior:

1. Open the playground
2. Make the screen width smaller to activate the overflow mode
3. Click on the overflow icons on both the Basic and the Text Only example
4. Basic TabContainer is working fine, Text Only Tab Container has the described issue

Expected behavior
A clear and concise description of what you expected to happen.
After clicking the left icon I expect the container to scroll to the left.

Context

• UI5 Web Components version: 0.7.0
• OS/Platform: MacOS Mojave 10.14.3
• Browser (if relevant): Chrome 72.0.3626.119

Affected components (if known)
TabContainer