By Blake Brittain and Stephen Nellis WASHINGTON/SAN FRANCISCO (Reuters) -Apple said on Wednesday it would remove a blood oxygen monitoring feature from two flagship Apple Watch models in the U.S. as the iPhone maker fights a legal battle over patents on the technology behind the feature. The legal fight could take a year to resolve, and analysts had expected Apple would strike the feature, which is marketed for fitness uses, rather than pull devices from sale in one of its biggest markets. The company said Apple Watch Series 9 and Ultra 2 models without the feature would go on sale on its webs…