finally use correct api key

frontend/android/app/build.gradle

@@ -3,17 +3,18 @@ plugins {
     id "kotlin-android"
     id "dev.flutter.flutter-gradle-plugin"
     id 'com.google.android.libraries.mapsplatform.secrets-gradle-plugin'
-
+    // last is probably not needed
 }
 
+def localPropertiesFile = rootProject.file('local.properties')
 def localProperties = new Properties()
-def localPropertiesFile = rootProject.file('secrets.properties')
+
 if (localPropertiesFile.exists()) {
     localPropertiesFile.withReader('UTF-8') { reader ->
         localProperties.load(reader)
     }
 } else {
-    throw new GradleException("Secrets file secrets.properties not found")
+    throw new GradleException("local.properties not found")
 }
 
 def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
@@ -26,6 +27,20 @@ if (flutterVersionName == null) {
     flutterVersionName = '1.0'
 }
 
+
+
+def secretPropertiesFile = rootProject.file('secrets.properties')
+def secretProperties = new Properties()
+
+if (secretPropertiesFile.exists()) {
+    secretPropertiesFile.withReader('UTF-8') { reader ->
+        secretProperties.load(reader)
+    }
+} else {
+    throw new GradleException("Secrets file secrets.properties not found")
+}
+
+
 android {
     namespace "com.example.fast_network_navigation"
     compileSdk flutter.compileSdkVersion
@@ -56,8 +71,8 @@ android {
         targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
-        // Placeholders of keys that are replaced by the build system.
-        manifestPlaceholders += [MAPS_API_KEY: "some value"]
+        // // Placeholders of keys that are replaced by the build system.
+        manifestPlaceholders += ['MAPS_API_KEY': secretProperties.getProperty('MAPS_API_KEY')]
 
     }