Save peer CSRK after ltk generation

Security level at stack side is determined after the LTK generation,
saving peer csrk info prior to this would result in saving security level as ZERO for peer CSRK info in to config file.
This can cause clearing the MITM_AUTH flag when CSRK info is loaded in the next BT session as security level is saved as ZERO for CSRK. Saving the peer CSRK after ltk generation would help in saving the right security level

This is a backport of aosp/3254899 against b#362322766.  Patches need to be included in the fix for b#288144143 to prevent regressions as described in b#428948282.

Test: mmm packages/modules/Bluetooth
Tag: #security
Bug: 288144143
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:ff015b002302669b55a18202a160426f86c1d9a5
Merged-In: I61bdd1f85e05388d0058b03fdc269f9eaca86c3f
Change-Id: I61bdd1f85e05388d0058b03fdc269f9eaca86c3f