Update demo app target SDKs to 34

This helps to highlight and document new requirements for apps,
e.g. to add the FOREGROUND_SERVICE_MEDIA_PLAYBACK permission for
background playback.

Issue: #11239
PiperOrigin-RevId: 548666056

constants.gradle

@@ -16,14 +16,14 @@ project.ext {
  releaseVersion = '2.19.0'
  releaseVersionCode = 2_019_000
     minSdkVersion = 16
-    appTargetSdkVersion = 33
+    appTargetSdkVersion = 34
     // API version before restricting local file access.
     // https://developer.android.com/training/data-storage/app-specific
     mainDemoAppTargetSdkVersion = 29
     // Upgrading this requires [Internal ref: b/193254928] to be fixed, or some
     // additional robolectric config.
     targetSdkVersion = 30
-    compileSdkVersion = 33
+    compileSdkVersion = 34
     dexmakerVersion = '2.28.3'
     junitVersion = '4.13.2'
     // Use the same Guava version as the Android repo: