EchoStar Corp. has agreed to sell spectrum licenses to AT&T Inc. for about $23 billion in a deal that may help the satellite telecommunications company stay afloat and fend off regulatory concerns about its airwave use.The sale will expand AT&T’s network and add about 50 MHz of low-band and mid-band spectrum in an all-cash transaction, the Dallas, Texas-based telecommunications company said in a statement on TuesdayBloomberg Terminal. The deal is expected to close by mid-2026, pending regulatory...