Sarah from Google told us in a Google AdWords Help thread that this label is now removed. She explained, "recently revamped the old Google Advertising Professional Program and relaunched the Google AdWords Certification Program." Due to that change Google has "removed the 'Google Advertising Professional' label from forum users until we can find a scalable way to relabel users who meet the new program qualifications."
So it may be back, but I don't expect it anytime soon.
Here is a before and after on a profile avatar:
I wonder if some will hold a revolt or not.
Forum discussion at Google AdWords Help.