Align avatar and commit content within commit row

## What does this MR do?
Aligns the user avatar on `Compare`

## What are the relevant issue numbers?
Closes #18787 

## Screenshots (if relevant)
<img src="/uploads/9525a599989f6a9faca54d9f9c62f755/Screen_Shot_2016-06-20_at_11.25.08_AM.png" width="800px">
<img src="/uploads/6c96ed629f377d69745548309006a520/Screen_Shot_2016-06-20_at_11.25.19_AM.png" width="800px">


See merge request !4764