Anvil: Fix everything to make it work with real assethub westend

[dimartiro]

Description

This PR enables forking from production chains like Westend Asset Hub by implementing dynamic transaction building and batch storage prefetching to address pallet index mismatches and reduce RPC latency.

Changes

Dynamic Transaction Building

When forking from a chain with a different runtime configuration, the hardcoded pallet index used by subxt_client::tx().revive().eth_transact() may not match the forked chain's pallet ordering, causing transaction failures. This PR introduces dynamic transaction building using subxt's dynamic_tx() which reads pallet indices from the runtime metadata at execution time, ensuring correct encoding regardless of the forked chain's configuration.

Batch Storage Prefetching

Each storage read from a remote chain requires an individual RPC call, causing significant latency during transaction validation. This PR implements batch prefetching using state_queryStorageAt to fetch multiple storage keys in a single RPC call. Before validating an Ethereum transaction, the sender's account info is prefetched to avoid sequential RPC round-trips.

Tests

• Updated test URL from local zombienet to real Westend Asset Hub RPC endpoint
• Added send_transaction_and_wait() and deploy_contract_and_wait() helpers that poll for transaction receipts with configurable timeouts, essential for reliable testing against remote networks with variable block times
• Removed forking-tests feature flag - forking tests now run without special configuration

All forking tests pass against real Westend Asset Hub