fix: prefer undefined fqbn over empty string

Author: Akos Kitta

arduino-ide-extension/src/node/boards-service-impl.ts

@@ -257,7 +257,7 @@ export class BoardsServiceImpl
           const platform = board.getPlatform();
           if (platform) {
             const platformId = platform.getId();
-            const fqbn = board.getFqbn();
+            const fqbn = board.getFqbn() || undefined; // prefer undefined over empty string
             const parsedPlatformId = createPlatformIdentifier(platformId);
             if (!parsedPlatformId) {
               console.warn(