Know if a commit is signed via the api

Hi,
I would like to add in my Forge application, a check that will verify that all the commits of the pull request are well signed. For this I can retrieve the list of commits of the PR, I can request the API for each commit. But I can’t find any information in the API return to know if the commit has been signed.
I would like to know this from the API to avoid having to load the GPG keys in a step to check each commit with the GIT commands.
Is it possible to retrieve this information from the API?

Regards,
Quentin