gradle: update to agp 9.1

The legacy kapt thing is a bummer. We'll need to move to ksp at some
point.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

gradle.properties

@@ -22,27 +22,6 @@ org.gradle.jvmargs=-Xmx1536m
 # Turn off AP discovery in compile path to enable compile avoidance
 kapt.include.compile.classpath=false
 
-# Experimental AGP flags
-# Generate compile-time only R class for app modules.
-android.enableAppCompileTimeRClass=true
-# Keep AAPT2 daemons alive between incremental builds.
-android.keepWorkerActionServicesBetweenBuilds=true
-# Generate manifest class as a .class directly rather than a Java source file.
-android.generateManifestClass=true
-
-# Default Android build features
-# Disable resource values generation by default in libraries
-android.defaults.buildfeatures.resvalues=false
-# Disable shader compilation by default
-android.defaults.buildfeatures.shaders=false
-# Disable Android resource processing by default
-android.library.defaults.buildfeatures.androidresources=false
-
-# Suppress warnings for some features that aren't yet stabilized
-android.suppressUnsupportedOptionWarnings=android.keepWorkerActionServicesBetweenBuilds,\
-  android.enableAppCompileTimeRClass,\
-  android.suppressUnsupportedOptionWarnings
-
 # OSSRH sometimes struggles with slow deployments, so this makes Gradle
 # more tolerant to those delays.
 systemProp.org.gradle.internal.http.connectionTimeout=500000