To manually update settings.gradle, follow these steps:

1. Copy `settings.gradle` as `settings_aar.gradle`
2. Remove the following code from `settings_aar.gradle`:

    def localPropertiesFile = new File(rootProject.projectDir, "local.properties")
    def properties = new Properties()

    assert localPropertiesFile.exists()
    localPropertiesFile.withReader("UTF-8") { reader -> properties.load(reader) }

    def flutterSdkPath = properties.getProperty("flutter.sdk")
    assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
    apply from: "$flutterSdkPath/packages/flutter_tools/gradle/app_plugin_loader.gradle"