Add a rule for /product-services partition.

Like /system and /product, /product-services will contain apps that
should have the same privileges as the one in other system partitions.

Bug: 80741439
Test: successfully tested e2e on two devices, one with
/product-services partition and another with /product-services
symlinking to -> /system/product-services
Change-Id: Ieee7a9a7641a178f44bb406dbdef39ed46713899

private/file_contexts

@@ -352,7 +352,12 @@
 #############################
 # Product files
 #
-/(product|system/product)(/.*)?               u:object_r:system_file:s0
+/(product|system/product)(/.*)?                                 u:object_r:system_file:s0
+
+#############################
+# Product-Services files
+#
+/(product-services|system/product-services)(/.*)?               u:object_r:system_file:s0
 
 #############################
 # Data files