Remove unused tag stage
What does this MR do?
The tag stage was added by Automatically tag on merge to main (!141 - merged) • Craig Smith • 16.0, however, the upsert-git-tag job which uses this stage was removed by Remove git upsert job as we use deploy script (!258 - merged) • Isaac Dawson, which should've also removed the tag stage. This MR removes this unused tag stage.