header: fix `aria-expanded` for user-menu dropdown
header: fix `aria-expanded` for user-menu dropdown

It's not expanded by default, so it needs `aria-expanded="false"`

Signed-off-by: XhmikosR <b60f67e10123951b393d9ba15dcf79efc14744bb@gmail.com>
jacobsalmela/AdminLTE,jacobsalmela/AdminLTE,jacobsalmela/AdminLTE,jacobsalmela/AdminLTE