Updates android-gradle-plugin to 9.2.1 (lint 32.2.1) and migrates off the org.jetbrains.kotlin.android plugin to AGP's built-in Kotlin, pinning the Kotlin version on each root's buildscript classpath and applying the com.android.library/application plugins through the plugins DSL. Differential Revision: https://phabricator.services.mozilla.com/D309476