Make font_fallback.xml unreadable

Bug: 281769620
Test: atest CtsGraphicsTestCases
Test: atest CtsTextTestCases
Change-Id: I05011c9313fa3818ec50d9884227512ef1b0fda9
diff --git a/private/system_server.te b/private/system_server.te
index dc6d322..f44eab1 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -1550,5 +1550,8 @@
 neverallow { domain -init -system_server } font_data_file:file no_w_file_perms;
 neverallow { domain -init -system_server } font_data_file:dir no_w_dir_perms;
 
+# Allow reading /system/etc/font_fallback.xml
+allow system_server system_font_fallback_file:file r_file_perms;
+
 # Allow system server to set dynamic ART properties.
 set_prop(system_server, dalvik_dynamic_config_prop)