LONDON—Bullish investors left the dollar near a one-week low and lifted riskier currencies such as the Australian dollar and British pound on Thursday, as fears about the fallout from Omicron were sidelined. The euro slipped by 0910 GMT but held above $1.13 while the dollar index, at 96.159, was unchanged on the day but near its weakest since last Friday. The risk-sensitive Australian dollar rose 0.3 percent to$0.7238 after Wednesday’s 0.86 percent surge. Sterling gained 0.2 percent to $1.3385 after a 0.63 percent rally. “AUD is as usual the flag-bearer for bullish sentiment about the world economy,” said Marshall Gittler, Head of Investment Research at BDSwiss Holding. Risk appetite has improved since Monday, when markets were rattled by government restrictions relating to the spread of Omicron. However, data on Wednesday showed U.S. consumer confidence improving more than expected in December, suggesting the economy would continue to expand in 2022 despite …