Fix chart loading on campaign selection
Fix chart loading on campaign selection

The ternary statement was backwards in the campaign
dropdown-value-changed handler. It was assigning null when there was a
campaign, and trying to read a campaign from the list of selected items
when the list was empty.

SeedScientific/polio,unicef/rhizome,SeedScientific/polio,unicef/rhizome,SeedScientific/polio,unicef/rhizome,unicef/polio,SeedScientific/polio,unicef/polio,unicef/polio,SeedScientific/polio,unicef/rhizome,unicef/polio