only count those who have found at least 1 cam as participant

src/model/highscore.rs

@@ -11,10 +11,11 @@ impl Backend {
     pub(crate) async fn amount_participants(&self) -> i64 {
         match self {
             Backend::Sqlite(db) => {
-                let row = sqlx::query!("SELECT COUNT(*) as count FROM client")
-                    .fetch_one(db)
-                    .await
-                    .unwrap();
+                let row =
+                    sqlx::query!("SELECT COUNT(DISTINCT client_uuid) AS count FROM sightings; ")
+                        .fetch_one(db)
+                        .await
+                        .unwrap();
 
                 row.count
             }