add exported flag (sdk 31 requirement)

Author: 05nelsonm

sampleapp/src/main/AndroidManifest.xml

@@ -15,9 +15,11 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name=".ui.MainActivity"
+        <activity
+            android:name=".ui.MainActivity"
+            android:exported="true"
             android:launchMode="singleInstance"
-            android:screenOrientation="portrait" >
+            android:screenOrientation="portrait">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />