House Democrats ended their 25-hour sit-in over gun control legislation on Thursday, a protest Speaker Paul D. Ryan labeled a high-profile stunt that undermined the basic institutions of government. Mr. Ryan said he was “not going to allow stunts like this to stop us from carrying out the people’s business.” He added, “This is about a publicity stunt and now a fund-raising scheme.” But on legislative business, it was Mr. Ryan who prevailed. He personally reclaimed control of the House, pounding his gavel and muscling through a major appropriations bill that included funding for combating the Zika virus, without debate.