Barbra Streisandallegedly forgot her comments on social media can be read by all — or at least, that’s the card she’s pulling after catching heat for asking Melissa McCarthy publicly if she’s on Ozempic, RadarOnline.com has learned. The 82-year-old All Night Long actress defended her weight loss question to McCarthy, 53, by taking to her public platform and explaining her question instead of apologizing for it. “OMG — I went on Instagram to see the photos we’d posted of the beautiful flowers I’d received for my birthday! Below them was a photo of my friend Melissa McCarthy who I sang with on m…