Flutter build Android error : A problem occurred evaluating project ':app'. No signature of method

I'm currently trying to upload my Flutter app to the Play Store. I followed the instruction on the Flutter documentation. But when I run the command "flutter build appbundle", I get the following error:

A problem occurred evaluating project ':app'. No signature of method: build_bobankfptw27tkl4q05osmwsd.android() is applicable for argument types: (build_bobankfptw27tkl4q05osmwsd$_run_closure2) values: [build_bobankfptw27tkl4q05osmwsd$_run_closure2@103337d8]

Here is the content of my build.gradle file.

def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

def keystoreProperties = new Properties()
def keystorePropertiesFile = rootProject.file('key.properties')
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
}

android {
    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    defaultConfig {
        applicationId "fr.mediprest"
        minSdkVersion 18
        targetSdkVersion 30
        compileSdkVersion 30
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

    signingConfigs {
        applicationId "fr.mediprest"
        minSdkVersion 18
        targetSdkVersion 30
        compileSdkVersion 30
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        release {
            keyAlias keystoreProperties['keyAlias']
            keyPassword keystoreProperties['keyPassword']
            storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
            storePassword keystoreProperties['storePassword']
        }
    }

    buildTypes {
        release {
            signingConfig signingConfigs.release
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
}

Does someone has any idea of what may cause this error?