LONDON (Reuters) – The British pound rebounded against the U.S. dollar on Wednesday as a drop in oil prices and an upswing in sentiment pushed the greenback rally triggered by Russia’s invasion of Ukraine into reverse. European and U.S. stock markets were staging a tentative rebound after four straight sessions of heavy losses with investors bargain hunting again amid fresh yet shaky optimism about a diplomatic solution to the conflict. The pound was up 0.48% at $1.3165 at 1607 GMT while the dollar index lost over 1% against its main currency rivals. The euro, also boosted by speculation of a …