Let the system server have CONNECTIVITY_USE_RESTRICTED_NETWORKS.

Also :
- Fix testUidFilteringDuringVpnConnectDisconnectAndUidUpdates that
  was failing on devices with a first released SDK >= Q
- Add a test actually tests that the system has the permission, as
  the test was only testing what's in the mock

Bug: 119770201
Test: New test making sure this stays true
Merged-In: I74cf5f0fa17fcf818f1fed78c7e3e4375c20152e
Change-Id: I0daa644fbad8e389ad7cfa66c0e3b3480c8bb50a
(cherry picked from commit 629b49d58fe8d108a3d7d47a21471aff913c6b34)
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index bff954d..ab7aed3 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -1697,6 +1697,7 @@
          @hide -->
     <permission android:name="android.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS"
         android:protectionLevel="signature|privileged" />
+    <uses-permission android:name="android.permission.CONNECTIVITY_USE_RESTRICTED_NETWORKS"/>
 
     <!-- @SystemApi Allows an internal user to set signal strength in NetworkRequest. This kind of
          request will wake up device when signal strength meets the given value.