feat: show feedback when map search yields no results

src/app/modules/map/page/map-page.component.ts

@@ -249,6 +249,15 @@ export class MapPageComponent {
         this.filterQuery,
         this.queryText,
       );
+      if (result.data.length === 0) {
+        const alert = await this.alertController.create({
+          buttons: [this.translateService.instant('ok')],
+          header: this.translateService.instant('map.page.NO_RESULTS'),
+        });
+        await alert.present();
+
+        return;
+      }
       // override items with results
       this.items = result.data as SCPlace[];
       this.addToMap(result.data as Array<SCBuilding | SCRoom>, true, animate);