ADFA-4128: exercise AGP_VERSION_LATEST on the Gradle the IDE now bundles

Stage's ADFA-2602 moved the on-device toolchain to AGP 9.3.1 / Gradle 9.6.1,
and AGP 9.3.1 refuses to configure on Gradle older than 9.5. The plugin
TestKit suite runs AGP_VERSION_LATEST against AGP_VERSION_GRADLE_LATEST, so
8.14.3 now fails every default-arm test with "Minimum supported Gradle
version is 9.5.0". Pin the bundled 9.6.1 instead.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NCnKjcRZvo4dTtCupzyt6t

Author: fryanpan

build-info/build.gradle.kts

@@ -76,9 +76,10 @@ tasks.create("generateBuildInfo") {
 						libs.versions.agp.tooling
 							.get(),
 					// The Gradle version AGP_VERSION_LATEST gets exercised against: the
-					// distribution the IDE bundles. 8.6 was stale - AGP 8.11 refuses to
-					// configure on anything older than 8.13.
-					"AGP_VERSION_GRADLE_LATEST" to "8.14.3",
+					// distribution the IDE bundles (GRADLE_DISTRIBUTION_VERSION in
+					// composite-builds/build-deps-common). AGP 9.3.1 refuses to configure
+					// on anything older than 9.5.
+					"AGP_VERSION_GRADLE_LATEST" to "9.6.1",
 					"SNAPSHOTS_REPOSITORY" to VersionUtils.SONATYPE_SNAPSHOTS_REPO,
 					"PUBLIC_REPOSITORY" to VersionUtils.SONATYPE_PUBLIC_REPO,
 				),