Accept KeyChain keys in WifiEnterpriseConfig.

Also removed unnecessary validation when removing a suggestion.

Bug: 160457441
Test: atest android.net.wifi
Test: atest com.android.server.wifi
Test: atest MixedDeviceOwnerTest#testAddNetworkWithKeychainKey_granted
Test: atest MixedDeviceOwnerTest#testAddNetworkWithKeychainKey_granted
Test: atest android.net.wifi.cts.WifiEnterpriseConfigTest
Change-Id: Ifa4817590932c37a75004392c6e3e4d5e526b85a
13 files changed