WASHINGTON — Hundreds came out to see the full dress rehearsal of the 32nd installment of “A Capitol Concert” this week. Although it was a walkthrough for the real event to take place on Fourth of July, the spirit of the celebration was in full swing. The rehearsal had to be delayed by an approaching thunderstorm, but it was well worth it for the few that stayed. About 300,000 people from around the country are expected to attend “A Capitol Concert.”