build: Bump AGP to 9.4.0 (#6070)

Raise the default Android Gradle Plugin from 9.2.1 to 9.4.0, the latest
stable release, and move the pinned lint version with it so lint keeps
matching the plugin it ships alongside.

Refresh the AGP compatibility matrix to 9.0.0/9.2.1/9.4.0. The minimum
supported 9.0.0 and the new default stay covered; 9.1.1 gives way to the
previous default 9.2.1 to keep the matrix at three jobs.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: runningcode

.github/workflows/agp-matrix.yml

@@ -17,7 +17,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        agp: [ '9.0.0', '9.1.1', '9.2.1' ]
+        agp: [ '9.0.0', '9.2.1', '9.4.0' ]
         integrations: [ true, false ]
 
     name: AGP Matrix Release - AGP ${{ matrix.agp }} - Integrations ${{ matrix.integrations }}

buildSrc/src/main/java/Config.kt

@@ -1,6 +1,6 @@
 
 object Config {
-    val AGP = System.getenv("VERSION_AGP") ?: "9.2.1"
+    val AGP = System.getenv("VERSION_AGP") ?: "9.4.0"
     val kotlinStdLib = "stdlib-jdk8"
     val kotlinStdLibVersionAndroid = "1.9.24"
     val kotlinTestJunit = "test-junit"

gradle.properties

@@ -13,7 +13,7 @@ android.useAndroidX=true
 # AGP 9+ migration opt-outs until we remove kotlin-android plugin and adopt built-in Kotlin.
 android.builtInKotlin=false
 android.newDsl=false
-android.experimental.lint.version=9.2.1
+android.experimental.lint.version=9.4.0
 
 # Release information
 versionName=8.56.0