When BN clock is out of sync, VC sets BN status to `BrokenClock`. It is
only reset to `Offline` after restoring time sync. However, if VC fails
encounters an error while checking time, Nimbus extensions are assumed
to be unavailable and the BN is no longer checked for having a synced
clock. This means it is never reset back to `Offline` if errors start
occurring _after_ BN is already set to `BrokenClock`. This could be
because BN is changed from Nimbus to an alternative implementation,
or due to intermittent connection issues.
Ensure that BN status is reset back to `Offline` when Nimbus extensions
are disabled to ensure eventual connection recovery.
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