default theme ID doesn't match comment in gitlab.yml

As part of upgrading to GitLab 11.0.3-ee we noticed the theme ID's had changed in config/gitlab.yml. So we updated the default_theme setting accordingly. 10.6:

     ## Default theme ID
     ##   1 - Indigo
     ##   2 - Dark
     ##   3 - Light
     ##   4 - Blue
     ##   5 - Green
     default_theme: 4 # default: 1

11.0:

     ## Default theme ID
     ##   1 - Indigo
     ##   2 - Light Indigo
     ##   3 - Blue
     ##   4 - Light Blue
     ##   5 - Green
     ##   6 - Light Green
     ##   7 - Red
     ##   8 - Light Red
     ##   9 - Dark
     ##   10 - Light
     default_theme: 3 # default: 1

Unfortunately that resulted in us having the Light theme as per the old IDs. Some experimenting shows that the original order is intact, and any new theme's simply have been tacked on to the end:

1 Indigo
2 Dark
3 Light
4 Blue
5 Green
6 Light Indigo
7 Light Blue
8 Light Green
9 Red
10 Light Red