default link styles conflict with editor button component link

[timelsass]

Describe the bug
Themes provide base styles for components, and one that's almost always present is for links. In testing a theme that has set a:hover, a:focus { text-decoration: underline; } (a common style), I noticed the published panel's "View Page" button inherits the underline from a since no overriding style is supplied.

To Reproduce
Steps to reproduce the behavior:

1. Create a new page/post.
2. Publish post (I have the "Always show pre-publish checks." option on).
3. Hover over the "View Page" link, and you will see the text is underlined.
4. Hover over the "Copy Link" button, and you will see the text is not underlined.
5. Repeat steps 3 & 4 with the focus state.

Expected behavior
I expect that the link styled to look like a button would have the same visual presentation in the various states like :hover and :focus.

Screenshots
Hover State:

Focus State:

Desktop (please complete the following information):
OS: Ubuntu 18.04.1 LTS
chrome
Version 69.0.3497.92 (Official Build) (64-bit)

Additional context
Replicated in Gutenberg Master Branch
Replicated in Gutenberg Plugin Version 4.1.1 svn