LONDON, March 16 : British teenagers, like their peers abroad, have a conflicted relationship with social media.  They know it can feed them a diet of "brain rot" content that keeps them glued to their phones while making money for big tech. Yet it is central to their lives, and many do not think it is the government's job to ban it.    Britain, like other countries in Europe and beyond, is considering ways to restrict social media after becoming increasingly aware of the risks to children. It