Amazon has ousted Roku as the TV adaptor of choice to go in Best Buy’s in-house TV brand, Insignia, as well as in other Toshiba smart TVs sold in the Best Buy stores. It all comes as part of a deal for Best Buy to sell on Amazon, and for Amazon to gain a valuable retail footprint in its war to keep Alexa ahead of Google Assistant in the US high street. The Insignia and Toshiba TVs at Best Buy include Fire TV technology built in. Insignia and Toshiba-branded Fire OS TV sets, called Fire TV Edition, will retail at Best Buy for something close to $400, with an Alexa-powered voice remote, and 4K UHD support – significantly undercutting most…