The basis of the GPL is copyright, so what you're really asking is whether you can use part of a copyrighted work in another work without infringing.
And the answer as always is "it depends".
And the answer as always is "it depends".
Whether the GPL2 will hold up in court, or whether the courts will uphold this specific case (e.g. can you prove intent? Do you need to?), is a separate issue entirely.
The next question is, can I use GPL'ed code in my product and then claim that it was injected by Copilot to avoid repercussions of my actions if caught?
But why would copilot do this? It's a language model not a database.
Not necessarily. Even 11k lines of copied code might fall under fair use, as Oracle recently discovered ;)