LDEV-3115 Properly set number of groups when opening a Run Sequence In original LD a number of groups can be set in a grouping activity. This number of groups can later change if a Monitor assigns learners to groups in Monitoring UI. When opening a Run Sequence, the grouping still holds old, lower value, but there are more existing groups. This leads on validation errors on re-save. Now the number of groups is maximum of the original number of groups and number of existing groups.