Fix spacing on icons for mobile button mode

[guiherzog]

Bug Report

Prerequisites

• Can you reproduce the problem in a MWE?
• Are you running the latest version?
• Did you check the FAQs to see if that helps you?
• Are you reporting to the correct repository?
• Did you perform a search in the issues?

Versions

v1.3.0

Description

When the button switches to full-width and it uses icons, it should keep the spacing between the icon and the text to 8px according to the specification on the design pattern.

Steps to Reproduce

1. Open precise-ui kitchen sink.
2. Check Button component.
3. Add icon to it.
4. Resize the screen to mobile view.

Expected behavior:
The spacing between the icon and the text is 8px;

Actual behavior:
The spacing between the icon and the text is fluid (space-between) and it grows when the buttons grows in width.