Changed build header username area to use the full name with the username as the tooltip

What does this MR do?

Changes build header username to use the full name with the username as the tooltip.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

UI consistency

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Contributes to #21832 (closed)

Added 1 commit:

• f099e36c - Change username full name back to only username on xs viewports

Reassigned to @fatihacet

Reassigned to @jschatz1

Milestone changed to %8.12

Milestone changed to %8.13

Was this hidden before? Where does it say we want this?

It's from point 4 of #21832 (closed), I also checked in Slack and response was that the builds page should have the same username header as issuables.

Reassigned to @lbennett

Reassigned to @jschatz1

Status changed to merged

Mentioned in commit b1947b71

Pick into Stable was missing!

Added ~149423 label

Picked into 8-13-stable, will go into 8.13.0-rc4.

Removed ~149423 label

Mentioned in commit d9601fca