[gnome-shell] Non-fast-forward update to branch wip/wjt/dont-set-welcome-dialog-last-shown-if-tour-not-installed

[Will Thompson <wjt src gnome org>]

The branch 'wip/wjt/dont-set-welcome-dialog-last-shown-if-tour-not-installed' was changed in a way that was 
not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  11af369... main: Only set last-shown-version if welcome actually shown

Commits added to the branch:

  2256173... main: Only set last-shown-version if welcome actually shown