Default Graffiti on `GE168dTK63af` like standard

[nalepae]

🚀 Feature Request

Description

From @barnabasbusa

All CLs default their graffiti to <EL Type><EL commit><CL type><CL commit> excepted Prysm.
Example: GE168dTK63af for go-ethereum commit 128d... and teku commit 63af...

• Specify Client Versions on Engine API ethereum/execution-apis#517

The following cat politely requests that Prysm comply with this standard.

[prestonvanloon]

Also see #13558