nandroid: exclude apexdata com.android.art folder from backup

- throws tar 255 error on AOSP Android 12

Change-Id: I2bad9c83c294d7b533c637b678764fdf25bc2cf0
(cherry picked from commit 80c92d9be2958b0e732a8be6afc2f85be788431b)
diff --git a/partition.cpp b/partition.cpp
index 3b85a8c..7e6fd55 100755
--- a/partition.cpp
+++ b/partition.cpp
@@ -1206,6 +1206,7 @@
 		backup_exclusions.add_absolute_dir("/data/per_boot"); // DJ9,14Jan2020 - exclude this dir to prevent "error 255" on AOSP ROMs that create and lock it
 		backup_exclusions.add_absolute_dir("/data/vendor/dumpsys");
 		backup_exclusions.add_absolute_dir("/data/cache");
+        backup_exclusions.add_absolute_dir("/data/misc/apexdata/com.android.art"); // exclude this dir to prevent "error 255" on AOSP Android 12
 		wipe_exclusions.add_absolute_dir(Mount_Point + "/misc/vold"); // adopted storage keys
 		ExcludeAll(Mount_Point + "/system/storage.xml");
 	} else {