ci: align MindMachine Android workflow with e-Sun setup

app/build.gradle.kts

@@ -1,3 +1,5 @@
+import java.util.Properties
+
 plugins {
     id("com.android.application")
     id("org.jetbrains.kotlin.android")
@@ -5,7 +7,17 @@ plugins {
     id("org.jetbrains.kotlin.plugin.compose")
 }
 
-import java.util.Properties
+val keystorePropertiesFile = rootProject.file("keystore.properties")
+val keystoreProperties = Properties()
+if (keystorePropertiesFile.exists()) {
+    keystorePropertiesFile.inputStream().use { keystoreProperties.load(it) }
+}
+val hasReleaseSigning = listOf(
+    "storeFile",
+    "storePassword",
+    "keyAlias",
+    "keyPassword",
+).all { !keystoreProperties.getProperty(it).isNullOrBlank() }
 
 android {
     namespace = "solutions.tretter.mindmachine"
@@ -21,25 +33,25 @@ android {
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }
 
-    buildTypes {
-        signingConfigs {
+    signingConfigs {
+        if (hasReleaseSigning) {
             create("release") {
-                val propsFile = rootProject.file("keystore/upload-keystore.properties")
-                if (propsFile.exists()) {
-                    val props = Properties().apply { propsFile.inputStream().use { this.load(it) } }
-                    storeFile = rootProject.file(props.getProperty("storeFile"))
-                    storePassword = props.getProperty("storePassword")
-                    keyAlias = props.getProperty("keyAlias")
-                    keyPassword = props.getProperty("keyPassword")
-                }
+                storeFile = file(keystoreProperties.getProperty("storeFile"))
+                storePassword = keystoreProperties.getProperty("storePassword")
+                keyAlias = keystoreProperties.getProperty("keyAlias")
+                keyPassword = keystoreProperties.getProperty("keyPassword")
             }
         }
+    }
 
+    buildTypes {
         debug {
             buildConfigField("boolean", "DEBUG_AD_FREE", "true")
         }
         release {
-            signingConfig = signingConfigs.getByName("release")
+            if (hasReleaseSigning) {
+                signingConfig = signingConfigs.getByName("release")
+            }
             isMinifyEnabled = false
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
@@ -88,7 +100,6 @@ dependencies {
     implementation("androidx.compose.material:material-icons-extended")
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.8.1")
 
-    // Monetization
     implementation("com.google.android.gms:play-services-ads:23.1.0")
     implementation("com.android.billingclient:billing-ktx:8.0.0")