ZURICH (Reuters) – The Swiss National Bank will keep intervening in foreign exchange markets to ensure price stability and needs to have lower interest rates than others to avoid an excessive appreciation of the Swiss franc, its vice chairman said in a newspaper interview. “Switzerland has always had lower rates than others since the financial crisis. It is very important for us to keep this differential to avoid an excessive appreciation of the Swiss franc,” Fritz Zurbruegg said in an interview with Swiss newspaper l’agefi published on Wednesday, but conducted last week before Russia invaded …