Benchmark cannot run in Android12 phone (#100761)

Author: JsouLiang

dev/benchmarks/macrobenchmarks/android/app/src/main/AndroidManifest.xml

@@ -23,6 +23,7 @@ found in the LICENSE file. -->
         <activity
             android:exported="true"
             android:name=".MainActivity"
+            android:exported="true"
             android:launchMode="singleTop"
             android:theme="@style/LaunchTheme"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"

dev/benchmarks/multiple_flutters/android/app/src/main/AndroidManifest.xml

@@ -13,6 +13,7 @@ found in the LICENSE file. -->
         android:theme="@style/Theme.MultipleFlutters">
         <activity
             android:name=".MainActivity"
+            android:exported="true"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
             android:hardwareAccelerated="true"
             android:windowSoftInputMode="adjustResize">

dev/benchmarks/platform_views_layout/android/app/src/main/AndroidManifest.xml

@@ -9,6 +9,7 @@ found in the LICENSE file. -->
 
     <application android:name="${applicationName}" android:label="platform_view_layout">
         <activity android:name=".DummyPlatformViewActivity"
+                  android:exported="true"
                   android:launchMode="singleTop"
                   android:theme="@android:style/Theme.Black.NoTitleBar"
                   android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"

dev/benchmarks/platform_views_layout_hybrid_composition/android/app/src/main/AndroidManifest.xml

@@ -9,6 +9,7 @@ found in the LICENSE file. -->
 
     <application android:name="${applicationName}" android:label="platform_view_layout">
         <activity android:name=".DummyPlatformViewActivity"
+                  android:exported="true"
                   android:launchMode="singleTop"
                   android:theme="@android:style/Theme.Black.NoTitleBar"
                   android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"