feat: add `server.hmr.update` to allow configuring ws settings while disabling HMR#20961

sapphi-red wants to merge 2 commits intovitejs:mainvitejs/vite:mainfrom

sapphi-red:feat/disable-hmr-but-configure-ws-settingssapphi-red/vite:feat/disable-hmr-but-configure-ws-settingsCopy head branch name to clipboard