By Michael Martina and David Brunnstrom WASHINGTON (Reuters) -China wants stabilized relations with the United States in the short term as it faces domestic economic challenges and push back in Asia to its assertive diplomacy, White House Indo-Pacific coordinator Kurt Campbell said on Thursday. Frustrations over China’s strict COVID-19 protocols boiled over into widespread protests last month, the biggest show of public discontent since President Xi Jinping came to power in 2012. The rules had contributed to a slowing economy, but the recent easing of restrictions have also created fresh conce…