WASHINGTON—The U.S. economy expanded at a 6.7 percent annual pace from April through June, the Commerce Department said Thursday, slightly upgrading its estimate of last quarter’s growth in the face of a resurgence of COVID-19 in the form of the delta variant. The government’s estimate of growth in the second quarter—its last of three—was up from its previous estimate of a 6.6 percent annual pace that will likely mark a high point for the economy’s expansion this year as the virus slows some activity, government support programs wind down and manufacturing supply-chain issues persist. Thursday’s report from the government showed that the nation’s gross domestic product—its total output of goods and services—accelerated from a 6.3 percent annual rate in the first three months of the year. A key factor in the upgraded growth estimate for the April-June quarter was a slightly higher level of consumer spending, which accounts for roughly …