WalletManager not aware of different Core-Versions (if more than one node configured)

The WalletManager is currently initialized with a `bitcoin_core_version_raw`. However, the wallet_manager is also a long living object managing more than one core-connection. Therefore the `bitcoin_core_version_raw` needs to be specific to the corresponding node-connection.

`bitcoin_core_version_raw` is used in the `create_wallet` method and needs to get fixed so that it's always asking the rpc for that info.

Start by locating WalletManager and its create_wallet method, then trace how each configured node connection exposes its RPC. Check where bitcoin_core_version_raw is initialized and used, and verify that create_wallet requests the version from the RPC associated with the node being managed rather than sharing one value across connections.

Written by the indexing model from the issue text.