Add label for charger property

Label charger property: ro.product.charger.unplugged_shutdown_time.

Bug: 267265061
Test: update the property in charger mode
Change-Id: I6c67123ac53f489851a8ad313e8aa40f67a3786e
diff --git a/private/property_contexts b/private/property_contexts
index 2db9da6..e29c58f 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -319,6 +319,7 @@
 ro.charger.                 u:object_r:charger_prop:s0
 sys.boot_from_charger_mode  u:object_r:charger_status_prop:s0 exact int
 ro.enable_boot_charger_mode u:object_r:charger_config_prop:s0 exact bool
+ro.product.charger.unplugged_shutdown_time  u:object_r:charger_config_prop:s0 exact int
 
 # Virtual A/B and snapuserd properties
 ro.virtual_ab.enabled   u:object_r:virtual_ab_prop:s0 exact bool