[TOFU] Don't send credentials in an unauthenticated TLS tunnel

Fix the security vulnerability reported in the security report.
Do not send the user credentials in phase2 before the user
approves the server certificate. This is done by connecting
with no credentials for the purpose of getting the server
certificate chain only, and reconnecting once the user approves
with full certificate chain authentication.

Updated-PDD: TRUE
Bug: 250574778
Bug: 251910611
Test: atest InsecureEapNetworkHandlerTest ClientModeImplTest
Test: Integration test with WPA-Enterprise network with an S
device and a T device.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:fb630e6a13189321d0e83037adc9e7b30dc6d796)
Merged-In: Ib3501f5e04881b11ea9ab52472dd233f2aa82c7a
Change-Id: Ib3501f5e04881b11ea9ab52472dd233f2aa82c7a
8 files changed