'Alert' icon should be replaced with 'Publish' icon in the 'Publish content' dialog

[dujes]

I'm submitting a...

• [x] Bug report
• [ ] Regression (a behavior that used to work and stopped working in a new release)
• [ ] Feature request
• [ ] Documentation issue or request

Context

Steps to Reproduce

1. Open the Settings of any course
2. Click on 'Publish' action
3. Observe icon visible next to the 'Publish Content' title

Expected Behavior

Icon should be matched with an icon visible in the Course Settings -> Actions -> Publish action.

Current Behavior

Warning icon is currently visible, the same as while deleting content.