Show policy transparency dialog for Wi-Fi network restrictions

- In order to support various user restrictions of individual Wi-Fi networks, WifiEntry provides the hasAdminRestrictions method for unified management.

- Settings will refer to WifiEntry#hasAdminRestrictions to restrict individual Wi-Fi networks.

Bug: 289448751
Bug: 289951241
Test: manual test
atest -c LongPressWifiEntryPreferenceTest

Change-Id: Iae5996a87ee72a3073300c7f62dfa14a9f31c21d