Fix locations and ps export (#953)

Author: idormenco

api/src/Vote.Monitor.Hangfire/Jobs/Export/Locations/ExportLocationsJob.cs

@@ -80,7 +80,7 @@ private async Task<LocationModel[]> GetLocationsAsync(Guid electionRoundId, Canc
                       "Level4",
                       "Level5",
                       "DisplayOrder",
-                      "Tags"
+                      coalesce("Tags", '{}') as "Tags"
                   FROM
                       "Locations"
                   WHERE

api/src/Vote.Monitor.Hangfire/Jobs/Export/PollingStations/ExportPollingStationsJob.cs

@@ -84,7 +84,7 @@ private async Task<List<PollingStationModel>> GetPollingStationsAsync(Guid elect
                       PS."Number",
                       PS."Address",
                       ps."DisplayOrder",
-                      PS."Tags"
+                      coalesce(PS."Tags", '{}') as "Tags"
                   FROM
                       "PollingStations" PS
                   WHERE