[wpa_supplicant] Generate more cert notification events

Starting a TOFU connection with the Android trust store is
desirable because it would allow authenticating networks that use
globally trusted Root CAs and not sending the Root CA during the
TLS handshake.
1. Do not drop certificate events if the sytem CA path was set.
2. Generate certificate events for the entire chain if validation
againts the trust store fails - this happens when the network has
its own private Root CA. The framework needs to do its own
validation before accepting a full chain.

Bug: 271921032
Test: Connect successfully and securely to WPA-Enterprise networks:
* Globally trusted Root CA
* Private Root CA with intermediates
* Partial / leaf only chain

Change-Id: Ia0540ca382f9587d89ec265d76aa9f366bab3303
2 files changed