PITTSBURGH — Republicans increasingly see one of the Democrats under consideration to be Vice President Kamala Harris’ running mate as the most likely to offer her a boost and make their efforts trickier: Pennsylvania Gov. Josh Shapiro. These Republicans say that Shapiro, a first-term governor of a critical swing state, is someone who could help broaden Harris’ appeal with independent voters and traditional Democrats who are drifting away from the party and help win over his home state — the most pivotal battleground on the presidential map, in their view. In Shapiro, they see a governor who not only won...