Change color of canceled ci text to gray

## What does this MR do?
Change text color of Canceled builds from `$gl-danger` to `$gl-gray`

## What are the relevant issue numbers?
Closes #18074 

## Screenshots (if relevant)
<img src="/uploads/f2ac59c5081c31cfb34bdc0470e31384/Screen_Shot_2016-06-01_at_10.38.17_AM.png" width="600px">

See merge request !4412