Add @Beta back to the new Invokable.getAnnotatedReturnType method of guava-android.

There is some chance that we will have to delete the method if we hear of problems under Android. And since it's a brand-new API _and_ it doesn't actually work under an Android VM, we know that we're affecting no existing users and possibly none even in the future.

RELNOTES=n/a
PiperOrigin-RevId: 523212269

Author: cpovirk

android/guava/src/com/google/common/reflect/Invokable.java

@@ -16,6 +16,7 @@
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
+import com.google.common.annotations.Beta;
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.annotations.DoNotCall;
@@ -366,6 +367,7 @@ abstract Object invokeInternal(@CheckForNull Object receiver, @Nullable Object[]
   @DoNotCall("fails under Android VMs; do not use from guava-android")
   @Deprecated
   @IgnoreJRERequirement
+  @Beta
   public abstract AnnotatedType getAnnotatedReturnType();
 
   static class MethodInvokable<T> extends Invokable<T, Object> {