Refactor betterPricesMap handling in RevenueSection for Vue 3 compatibility

- Removed the use of $set for updating betterPricesMap, leveraging direct assignment instead, which is now the standard in Vue 3.
- Simplified the getBetterPrices method by eliminating unnecessary logging, enhancing code clarity while maintaining functionality.
- These changes aim to improve performance and align with Vue 3 best practices for state management.

frontend/src/components/falukant/RevenueSection.vue

@@ -130,22 +130,19 @@
                 currentRegionId: this.currentRegionId
               }
             });
-            console.log(`[RevenueSection] Product ${product.id} (${product.labelTr}): received ${data?.length || 0} better prices:`, data);
             // Speichere betterPrices in einem separaten Map, nicht auf dem product Objekt
-            this.$set(this.betterPricesMap, product.id, data || []);
-            console.log(`[RevenueSection] betterPricesMap after update:`, JSON.parse(JSON.stringify(this.betterPricesMap)));
+            // In Vue 3 ist $set nicht mehr nötig, direkte Zuweisung funktioniert
+            this.betterPricesMap[product.id] = data || [];
           } catch (error) {
             console.error(`Error loading prices for product ${product.id}:`, error);
-            this.$set(this.betterPricesMap, product.id, []);
+            this.betterPricesMap[product.id] = [];
           } finally {
             this.loadingPrices.delete(product.id);
           }
         }
       },
       getBetterPrices(productId) {
-        const prices = this.betterPricesMap[productId] || [];
-        console.log(`[RevenueSection] getBetterPrices(${productId}): returning`, prices);
-        return prices;
+        return this.betterPricesMap[productId] || [];
       },
       getCityPriceClass(branchType) {
         if (branchType === 'store') return 'city-price-green';