RootCanal: Properly determine link key type

* Partially support P256 SC authentication
* Determine link key type from SC and IO capabilities

Tag: #feature
Test: atest liblmp_tests
Bug: 238092436
Bug: 245578454
Ignore-AOSP-First: cherry-pick from AOSP
Merged-In: I00673f011d944ddf5ccce748cad2a4ac4770e6bc
Change-Id: I00673f011d944ddf5ccce748cad2a4ac4770e6bc
(cherry picked from commit 63eff9a9)