SAN DIEGO — San Diego veterans and LGBT activists are celebrating the announcement Monday that transgender people will be allowed to serve in the military. President Joe Biden signed an executive order reversing a Trump-imposed ban, one of many signed in the first week of the new president’s term as he seeks to undo many of the policies of the last administration. “It is my conviction as Commander in Chief of the Armed Forces that gender identity should not be a bar to military service,” Biden’s executive order says. “Moreover, there is substantial evidence that allowing transg...