WifiNetworkSpecifier: Ensure we don't match a regular wifi network

In Android 10, ClientModeImpl would always attach a
WifiNetworkAgentSpecifier for all wifi network agents created
(regardless of whether it was created in response to a specific request
or not). In Android 11, we changed that behavior to ensure that we
attach the WifiNetworkAgentSpecifier only for agents created in response
to a specific request. However, that is exposing a bug in
WifiNetworkSpecifier matching. WifiNetworkSpecifier attached requests
should not satisfy a generic wifi network agent. Fix the
canSatisfiedBy() matching to ensure that it only matches
WifiNetworkAgentSpecifier (or itself which cannot happen during network
matching)

Bug: 149500993
Test: Add a saved network manually while running the failing ACTS test:
act.py -c wifi_manager_cross.config -tb dut-name -tc WifiNetworkRequestTest:
test_match_failure_with_invalid_ssid_pattern
Test: atest android.net.wifi

Change-Id: I38d154bd0a5685fcc38de891256a8e1d4b8cfbb5