Revert AGP to 8.8.1.

There is an issue when building the release version of the app.

Author: bmarty

gradle/libs.versions.toml

@@ -3,7 +3,7 @@
 
 [versions]
 # Project
-android_gradle_plugin = "8.9.0"
+android_gradle_plugin = "8.8.1"
 kotlin = "2.1.10"
 kotlinpoet = "2.1.0"
 ksp = "2.1.10-1.0.31"