Steps to reproduce (assumes ChromeVox or similar)

1. Create a new job or open an existing job
2. Navigate to the Single Metric Viewer
3. Tab to the table at the bottom
4. Tab to the Gear Icon

Actual Result

4. "Select Action - button" is read

Expected Result

4. Screen reader should relay some information about the row it's on "Select Action from November 29th.." etc

Meta Issue #26855

Kibana Version: 6.5

Relevant WCAG Criteria: 2.4.6 Headings and Labels