METALS-London aluminium resumes decline as LME reassesses Rusal metal

(Adds broker comment, updates prices) BEIJING, April 26 (Reuters) - London aluminium slipped again on Thursday, after snapping a four-day losing streak in the previous session, as the deadline extension to comply with U.S. sanctions on Rusal, one of the world's biggest aluminium producers, pulled down prices. The metal is down by around 18.6 percent from the seven-year high of $2,718 it hit on April 19 in the wake of the sanctions, which left the market fearing a supply shortage. Al