A CNN commentator unloaded on a Republican former gubernatorial candidate on Monday night during a discussion on the upcoming vice presidential debate and former President Donald Trump’s increasingly “dark” rhetoric. CNN anchor Kaitlan Collins noted to her panel on “The Source” that the race between Sen. J.D. Vance (R-OH) and Minnesota Gov. Tim Walz has been “really personal,” and could set it apart from previous vice presidential debates, which are typically substantive. The segment came with the backdrop that Trump attacked Vice President Kamala Harris as “mentally impaired” and “disabled” d…