config: Include androidx.window.extensions in tablet builds

This enables 2-pane layout in Settings for Android 12L.

Change-Id: I57af5b876c2c33897bf4047a70c10750785a3c76
diff --git a/config/common_mini_tablet.mk b/config/common_mini_tablet.mk
index f630e28..44dcfb9 100644
--- a/config/common_mini_tablet.mk
+++ b/config/common_mini_tablet.mk
@@ -3,6 +3,7 @@
 
 # Required packages
 PRODUCT_PACKAGES += \
+    androidx.window.extensions \
     LatinIME
 
 $(call inherit-product, vendor/bliss/config/telephony.mk)