visual styling changes to components and static pages in order to use updated icon button styling for duplicate and delete actions
adjusted unit_spec.js to reflect new HTML structure, and corrected screenreader label for delete button
updated static pages tests to reflect html element change in component.html
fixed typo in comment for assets.scss
Merge pull request #2276 from edx/studio/duplicate/visuals

Updates Studio's visual styling of action buttons on components and static pages