Document that all transactions are returned inline in /block response

The Rosetta spec defines an optional `other_transactions` field in `BlockResponse` for implementations that return transaction hashes separately from full transaction data. The previous TS implementation (`cardano-foundation/cardano-rosetta`) used this field when a block exceeded `PAGE_SIZE` transactions (see [Tatum's guide on this behavior](https://docs.tatum.io/docs/cardano-rosetta-block-method-and-other_transactions)).

Our Java implementation always returns all transactions inline in `block.transactions` and never populates `other_transactions`. This is a valid choice per spec, but it's not documented anywhere. Integrators coming from the TS implementation (or reading the generic Rosetta spec) may implement unnecessary `/block/transaction` calls.

Suggest adding a note to the `/block` section in [Cardano Addons](https://cardano-foundation.github.io/cardano-rosetta-java/core-concepts/cardano-addons#block) and/or the [BlockResponse](https://cardano-foundation.github.io/cardano-rosetta-java/api/#model/BlockResponse) API reference clarifying this behavior.