Fix off by one error for username colors
Fix off by one error for username colors

The hash result would only have a range of 0..7, but the css of color variants is 1..8
matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk