Steps to Reproduce
In order to replicate the behavior, please provide a detailed list of steps:

1. Start nethermind without CL started
2. Wait until UpdatingPivot stage would timeout (15 minutes)
3. Stop nethermind
4. Start CL and wait for it to sync
5. Start nethermind

Actual behavior
Beacon Headers phase can't be finished because of missing headers for new pivot

Expected behavior
With timeout disabled this case will not happen unless someone would force that with custom params