transaction: Change `bestChainBlockIncluded` to `Included`

The server should report the inclusion of a transaction in any block its seeing, not only what it assumes to be the best block. Best block is any way a highly opinionated view of the server. There are several factors that can determine on what is the actual best block (e.g. on going disputes etc). Another reason why the server return Included for every block are parachains. Parachains are determining on what is the best block by checking what is the best block of the relay chain. This means currently it takes at least around 12 seconds to get any kind of feedback on your transaction. While, the transaction is probably already in a block that it just waiting to get included in the relay chain.

The most important event for dapps/wallets should be the finalized one any way, as it is then clear that the changes are not getting reverted. If we in between reported multiple blocks that included the transaction, shouldn't change anything.

Review the transaction status terminology around bestChainBlockIncluded, Included, and finalized, using the issue rationale about parachains as context. Update the interface specification so inclusion is reported for every containing block while finalized remains the terminal confirmation, then verify the wording is consistent across the affected status definitions.