BLACKSTONE, Va. Khalani Jennings, a 7-year-old from Blackstone, Virginia, rang the bell this month, officially marking the end of her cancer treatment. Her cancer journey started in the fall when Khalani was experiencing unbearable pain on her right side. Her mom took her to the Children's Hospital of Richmond at VCU where, in October, she was diagnosed with a large cancerous tumor on her liver. "It was an embryonal sarcoma, which is very rare,"…