Support return booleans from the API

compendium-frontend/src/helpers/dataconversion.tsx

@@ -476,16 +476,22 @@ export function createMatrixDataLookup<Datatype extends NrenAndYearDatapoint>(da
     const dataLookup = new Map<string, Map<string, Map<number, Datatype>>>();
 
     data.forEach(entry => {
+        let value = entry[columnProperty];
+        if (typeof value === "boolean") {
+            value = value ? "True" : "False";
+        }
+
         let nrenEntry = dataLookup.get(entry.nren);
         if (!nrenEntry) {
             nrenEntry = new Map<string, Map<number, Datatype>>();
         }
-        let serviceEntry = nrenEntry.get(entry[columnProperty]);
+
+        let serviceEntry = nrenEntry.get(value);
         if (!serviceEntry) {
             serviceEntry = new Map<number, Datatype>();
         }
         serviceEntry.set(entry.year, entry);
-        nrenEntry.set(entry[columnProperty], serviceEntry);
+        nrenEntry.set(value, serviceEntry);
         dataLookup.set(entry.nren, nrenEntry);
     });
     return dataLookup;