Fix Kotlin syntax in Android example

Signed-off-by: Shengqi Chen <harry-chen@outlook.com>

Author: Harry-Chen

example/.gitignore

@@ -31,7 +31,6 @@
 /build/
 
 # Web related
-lib/generated_plugin_registrant.dart
 
 # Exceptions to above rules.
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages

example/android/app/src/main/kotlin/im/nfc/flutter_nfc_kit/example/MainActivity.kt

@@ -25,6 +25,7 @@ class MainActivity : FlutterActivity() {
     }
 
     override fun onNewIntent(intent: Intent) {
-        intent.getParcelableExtra(NfcAdapter.EXTRA_TAG)?.apply(FlutterNfcKitPlugin::handleTag)
+        val tag: Tag? = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG)
+        tag?.apply(FlutterNfcKitPlugin::handleTag)
     }
 }