Make font_fallback.xml unreadable

Bug: 281769620
Test: atest CtsGraphicsTestCases
Test: atest CtsTextTestCases
Change-Id: I05011c9313fa3818ec50d9884227512ef1b0fda9
diff --git a/private/file_contexts b/private/file_contexts
index 544d051..6acaf9d 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -350,6 +350,7 @@
 /system/etc/cgroups\.json               u:object_r:cgroup_desc_file:s0
 /system/etc/task_profiles/cgroups_[0-9]+\.json               u:object_r:cgroup_desc_api_file:s0
 /system/etc/event-log-tags              u:object_r:system_event_log_tags_file:s0
+/system/etc/font_fallback.xml           u:object_r:system_font_fallback_file:s0
 /system/etc/group                       u:object_r:system_group_file:s0
 /system/etc/ld\.config.*                u:object_r:system_linker_config_file:s0
 /system/etc/passwd                      u:object_r:system_passwd_file:s0