Implement WifiNetworkSpecifier#redact.

This is needed so that if an app files a NetworkRequest or
NetworkCallback with a WifiNetworkSpecifier and null UIDs,
sensitive information is redacted. Otherwise, the request could
match WifiNetworkAgentSpecifier of a connected wifi network, and
thus learn if a network is available that matches the specifier
it constructed.

Bug: 187921303
Test: atest WifiNetworkSpecifierTest#testRedact
Change-Id: Ie0f1b6168854b93a456f33913f34a07ef601140b
2 files changed