fae3a1f006 log: use error level for critical log messages (MarcoFalke)
Pull request description:
This picks up the first commit from https://github.com/bitcoin/bitcoin/pull/29231, but extends it to also cover cases that were missed in it.
As per https://github.com/bitcoin/bitcoin/blob/master/doc/developer-notes.md#logging, LogError should be used for severe problems that require the node to shut down.
ACKs for top commit:
stickies-v:
re-ACK fae3a1f006, I'm ~0 on the latest force push as `user_error` was already logged at the right level through `GetNotifications().fatalError(user_error);` so I'd be in favour of deduplicating/cleaning up this logging logic but can be done in follow-up.
kevkevinpal:
ACK [fae3a1f](fae3a1f006)
achow101:
ACK fae3a1f006
Tree-SHA512: 3f99fd25d5a204d570a42d8fb2b450439aad7685692f9594cc813d97253c4df172a6ff3cf818959bfcf25dfcf8ee9a9c9ccc6028fcfcecdb47591e18c77ef246