sepolicy: add permissions for trace reporting

Bug: 205892741
Change-Id: I1b6b2ebeae99ca6a9725f24564386cea78403c6d
diff --git a/private/system_server.te b/private/system_server.te
index 68792e8..ee454a6 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -524,9 +524,9 @@
 allow system_server prereboot_data_file:dir rw_dir_perms;
 allow system_server prereboot_data_file:file create_file_perms;
 
-# Allow dropbox to read /data/misc/perfetto-traces. Only the fd is sent over
+# Allow tracing proxy service to read traces. Only the fd is sent over
 # binder.
-allow system_server perfetto_traces_data_file:file read;
+allow system_server perfetto_traces_data_file:file { read getattr };
 allow system_server perfetto:fd use;
 
 # Manage /data/backup.