fixup! editor: fix memory corruption when creating advanced dialog

Don't leak the string.
2 jobs for bg/auth-dialog-fix in 6 minutes and 37 seconds (queued for 4 seconds)
latest
Status Job ID Name Coverage
  Build
passed #122596
fedora28_dist

00:03:32

 
  Test
passed #122597
fedora_from_dist

00:03:04