Remove flags for b#314331379

bluffs_mitigation has passed soak and flags for it should be removed.

Bug: 314331379
Bug: 319541706
Flag: bluffs_mitigation
Test: m libbluetooth
Tag: #security
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:9fc2e1e6d449e2665fc5d5d9af4ca87346863960)
Merged-In: I2f2743e1bec281823cd0ca4cb67e281f3aa1df48
Change-Id: I2f2743e1bec281823cd0ca4cb67e281f3aa1df48