Meghan Markle's half-sister Samantha Markle is reportedly being lined up to appear on the British version of Celebrity Big Brother as Viacom-owned broadcaster Channel 5 eyes a controversial theme. The network is theming this summer's reality hit as The Eye of The Storm and is expected to introduce housemates that have all been caught up in their own media controversies. The entrance of Samantha Markle, otherwise known as Samantha Grant, would make perfect sense given her…