feat(profile): integrate fsp with apt and ubuntu.

apparmor.d/groups/apt/dpkg-scripts

@@ -47,6 +47,7 @@ profile dpkg-scripts @{exec_path} {
   @{sbin}/update-rc.d                             Cx -> rc,
 
   # Maintainer scripts can legitimately start/restart anything
+  # PU is only used as a safety fallback.
   @{bin}/**                                       PUx,
   @{sbin}/**                                      PUx,
   @{lib}/**                                       PUx,
@@ -75,6 +76,8 @@ profile dpkg-scripts @{exec_path} {
     include <abstractions/app/bus>
     include <abstractions/bus-system>
 
+    capability dac_read_search,
+
     dbus send bus=system path=/
          interface=org.freedesktop.DBus
          member=ReloadConfig