Sync check not correct

[sander2]

We currently check if the bitcoin chain has been synced like this:

interbtc-clients/bitcoin/src/lib.rs

Line 394 in e6ee91d

if !info.initial_block_download || info.verification_progress.eq(&1.0) {

However, neither initial_block_download nor verification_progress can be relied upon, see bitcoin/bitcoin#26432 and bitcoin/bitcoin#26433

According to stackexchange we should compare the blocks and headers fields - if they are equal then the bitcoin node is synced.