Revert "fix(server): application/json header for notifictions"#1388

mattzcarey wants to merge 2 commits intomainmodelcontextprotocol/typescript-sdk:mainfrom

revert-1373-fix-json-header-notifsmodelcontextprotocol/typescript-sdk:revert-1373-fix-json-header-notifsCopy head branch name to clipboard