Increase default `dust_limit_satoshis` for 0-fee HTLC transactions

[t-bast]

We should update our default dust_limit_satoshis to 4 000 sats since we're now always using 0-fee HTLC transactions. This requires other implementations to accept it though, so we need the following issues to be closed and the corresponding implementation to be released:

• Don't reject high remote dust_limit_satoshis when anchor_outputs_zero_fee_htlc_tx is used lightningnetwork/lnd#10375
• Don't reject high remote dust_limit_satoshis when anchor_outputs_zero_fee_htlc_tx is used lightningdevkit/rust-lightning#4225

Note that cln already allows using a high dust_limit_satoshis value.