External inputs are currently only supported for initial transaction creation functions. Extend `solving_data` arguments as necessary to support fee bumping wallet transactions with non-wallet inputs.

https://github.com/bitcoin/bitcoin/pull/17211#issuecomment-897653994
#include <interfaces/wallet.h>
#include <consensus/amount.h>
#include <interfaces/chain.h>
#include <interfaces/handler.h>
#include <policy/fees.h>
#include <primitives/transaction.h>
#include <rpc/server.h>
#include <script/standard.h>
#include <support/allocators/secure.h>
#include <sync.h>
#include <uint256.h>
#include <util/check.h>
#include <util/system.h>
#include <util/translation.h>
#include <util/ui_change_type.h>
#include <wallet/context.h>
#include <wallet/feebumper.h>
#include <wallet/fees.h>
#include <wallet/ismine.h>
#include <wallet/load.h>
#include <wallet/receive.h>
#include <wallet/rpc/wallet.h>
#include <wallet/spend.h>
#include <wallet/wallet.h>
#include <memory>