Update kotlin monorepo to v2.4.0

Author: renovate[bot]

wireguard_plugin/android/build.gradle

@@ -1,6 +1,6 @@
 
 buildscript {
-    ext.kotlin_version = "2.1.0"
+    ext.kotlin_version = "2.4.0"
     repositories {
         google()
         mavenCentral()