Allow mediaprovider and mediaserver to read sdk_sandbox_data_file

Context: go/videoview-local-sandbox. This change is required to
play local files in a VideoView in the SDK sandbox.

Test: Manual steps described in doc
Bug: 266592086
Change-Id: I940609d5dff4fc73d0376489646488c7b96eebb8
diff --git a/private/mediaserver.te b/private/mediaserver.te
index aaf49f6..f44cbde 100644
--- a/private/mediaserver.te
+++ b/private/mediaserver.te
@@ -19,6 +19,9 @@
 # Allow mediaserver to start media.transcoding service via ctl.start.
 set_prop(mediaserver, ctl_mediatranscoding_prop);
 
+# Allow mediaserver to read SDK sandbox data files
+allow mediaserver sdk_sandbox_data_file:file { getattr read };
+
 # Needed for stats callback registration to statsd.
 allow mediaserver stats_service:service_manager find;
 allow mediaserver statsmanager_service:service_manager find;