如何在Splashscreen API中移除我的闪屏图标周围的圆形遮罩？

我有一个单一活动的应用程序，我正在使用SplashScreen API。我为我的图标使用了一个图层列表drawable，但它周围似乎有一个圆形的框架。我试着只使用图标的png文件，但我仍然有同样的问题。

styles.xml

<style name="Theme.App.Starting" parent="Theme.SplashScreen">
        // Set the splash screen background, animated icon, and animation duration.
        <item name="windowSplashScreenBackground">@color/sailor_blue</item>
        // Use windowSplashScreenAnimatedIcon to add either a drawable or an
        // animated drawable. One of these is required.
        <item name="windowSplashScreenAnimatedIcon">@drawable/splash_screen_layer_list</item>
        // Set the theme of the Activity that directly follows your splash screen.
        <item name="postSplashScreenTheme">@style/Theme.SimpleCrypto.NoActionBar</item>
    </style>
splash_screen_layer_list.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@color/sailor_blue" />
        android:drawable="@drawable/simple_crypto_logo"
        android:gravity="center" />
</layer-list>
Android Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.decagon.anietie.simplecrypto" >
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.SimpleCrypto"
        android:name=".SimpleCryptoApplication">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:label="@string/app_name"
            android:windowSoftInputMode="adjustResize"
            android:resizeableActivity="true"
            android:theme="@style/Theme.App.Starting"
            tools:targetApi="24" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <meta-data
            android:name="preloaded_fonts"
            android:resource="@array/preloaded_fonts" />
    </application>
</manifest>
而这是我的MainActivity文件
MainActivity.kt
class MainActivity : AppCompatActivity() {
    private lateinit var appBarConfiguration: AppBarConfiguration
    private lateinit var binding: ActivityMainBinding
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // Handle the splash screen transition.
        val splashScreen = installSplashScreen()
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)
        setSupportActionBar(binding.appBarMain.toolbar)
        val navController = findNavController(R.id.nav_host_fragment_content_main)
        binding.navView?.let {
            appBarConfiguration = AppBarConfiguration(
                setOf(
                    R.id.nav_home, R.id.nav_converter, R.id.nav_wallet, R.id.nav_settings
                binding.drawerLayout
            setupActionBarWithNavController(navController, appBarConfiguration)
            it.setupWithNavController(navController)
        binding.appBarMain.contentMain.bottomNavView?.let {
            appBarConfiguration = AppBarConfiguration(
                setOf(
                    R.id.nav_home, R.id.nav_converter, R.id.nav_wallet
            setupActionBarWithNavController(navController, appBarConfiguration)
            it.setupWithNavController(navController)
        onDestinationChangedListener()