Revert "Temporarily not inheriting updatable_apex.mk"

This reverts commit c5fc637c208e0bb059b7138422c22e7931f3a8d0.

Reason for revert: all Pixels (except pixel 1) are ready to support updatable APEX

Bug: 129035564
Test: run camera tests

Change-Id: Ib01a97db857ad928d875d244dcd0b3cac8e080ee
diff --git a/target/product/mainline_system.mk b/target/product/mainline_system.mk
index fc5c554..66207df 100644
--- a/target/product/mainline_system.mk
+++ b/target/product/mainline_system.mk
@@ -19,9 +19,7 @@
 $(call inherit-product, $(SRC_TARGET_DIR)/product/telephony_system.mk)
 $(call inherit-product, $(SRC_TARGET_DIR)/product/languages_default.mk)
 # Enable updating of APEXes
-# TODO(b/130652892, b/129035564): uncomment following line when Pixel 2019 kernel
-# is updated to support APEX.
-#$(call inherit-product, $(SRC_TARGET_DIR)/product/updatable_apex.mk)
+$(call inherit-product, $(SRC_TARGET_DIR)/product/updatable_apex.mk)
 # Add adb keys to debuggable AOSP builds (if they exist)
 $(call inherit-product-if-exists, vendor/google/security/adb/vendor_key.mk)