android: add style to test apk's

test/android/cmake/AndroidManifest.xml.cmake

@@ -43,8 +43,8 @@
         android:roundIcon="@mipmap/sdl-test_round"
         android:label="@string/label"
         android:supportsRtl="true"
-        android:hardwareAccelerated="true"
-        tools:targetApi="31">
+        android:theme="@style/AppTheme"
+        android:hardwareAccelerated="true">
         <activity
             android:name="@ANDROID_MANIFEST_PACKAGE@.SDLTestActivity"
             android:exported="true"

test/android/res/values/styles.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="android:Theme.NoTitleBar.Fullscreen">
+        <!-- Customize your theme here. -->
+    </style>
+</resources>