Support searching btc txid which is a L1 -> L2 transaction

[Keith-CY]

A validation of RGB++ commitment was added recently, and if a BTC tx without commitment will be ignored even an RGB++ Lock points to it, because it's not an isomorphic binding transaction.

But it introduced an exception that searching for an L1 -> L2 transaction by btc txid doesn't work. L1 -> L2 transaction doesn't require a commitment in the BTC tx, so it's ignored by CKB Explorer.

Here's how to improve:

1. sync btc txid if it's a L1 -> L2 transaction(RGB++ Lock in inputs but not in outputs)
2. support searching btc txid of an L1 -> L2 transaction
3. keep btc txid of an L1 -> L2 invisible on the transaction page