Add ueventd to mnt_vendor_file neverallow exemption list

Legacy hardware and code still depends on the ueventd helpers to
locate the firmware supported files which are on new mount path
labeled with mnt_vendot_file. For ueventd helper to work we need dir search
and read permission on this new label so moving ueventd to exempted list.

Already ueventd has the vendor_file_type read access.

Bug:110083808
Bug:111906767

Change-Id: Ia15cc39ecef9e29b4f1f684efdddbeb78b427988
Merged-In: Ia15cc39ecef9e29b4f1f684efdddbeb78b427988
(cherry picked from commit 44ae7c2c)

prebuilts/api/28.0/public/domain.te

@@ -1396,4 +1396,5 @@ userdebug_or_eng(`
 neverallow {
   coredomain
   -init
+  -ueventd
 } mnt_vendor_file:dir *;

public/domain.te

@@ -1396,4 +1396,5 @@ userdebug_or_eng(`
 neverallow {
   coredomain
   -init
+  -ueventd
 } mnt_vendor_file:dir *;