It's not a useful phrase because a "we accept AI-generated contributions" is also virtue signalling.

You have no doubt heard claims that AI "democratizes" software development. This is an argument that AI use for that case is virtuous.

You have no doubt heard claims that AI "decreases cognition ability." This is an argument that not using AI for software development is virtuous.

Which is correct depends strongly on your cultural views. If both are correct then the term has little or no weight.

From what I've seen, the term "virtue signalling" is almost always used by someone in camp A to disparage the public views of someone in camp B as being dishonest and ulterior to the actual hidden reason, which is to improve in-group social standing.

I therefore regard it as conspiracy theory couched as a sociological observation, unless strong evidence is given to the contrary. As a strawman exaggeration meant only to clarify my point, "all right-thinking people use AI to write code, so these are really just gatekeepers fighting to see who has the longest neckbeard."

Further, I agree with the observation at https://en.wikipedia.org/wiki/Virtue_signalling that "The concept of virtue signalling is most often used by those on the political right to denigrate the behaviour of those on the political left". I see that term as part of "culture war" framing, which makes it hard to use that term in other frames without careful clarification.