Prevent interleaved verification

Committing a session twice in a row will result in interleaved
verification flows and break the internal states.

Add a field to prevent this from happening if the verification
is already in progress.

Bug: 256330705
Test: manual test
Change-Id: I7e8a2fa7333d05a226268b325338e3fac69ddae0
Merged-In: I7e8a2fa7333d05a226268b325338e3fac69ddae0
(cherry picked from commit da7d72d88b9c45b4727deb100b92071b3f9a604e)
1 file changed