Added new logs and improved coverage for Wallets operations

[tomas-martins-crossmint]

This pull request adds comprehensive wallet logging to match the web SDK, updates the structure for logs sent to DataDog, and replaces OSLogType with a custom LogLevel type

New Logging Coverage

Added new log event constants and implemented logging across:

• DefaultSmartWalletService requests: createWallet, getWallet, transferToken
• SDK Initializer: Initial wallet service setup
• EVM Wallet: sendTransaction, signMessage, signTypedData
• Solana Wallet: sendTransaction
• Wallet Operations: approve
• Wallet Factory: Invalid chain error scenarios

All logs follow a three-phase pattern from the web SDK, (start → success/error) with contextual metadata (transaction IDs, addresses, chain types, error messages)

Structured Logging

Updated DataDogLoggerProvider and OSLoggerProvider to format messages with key=value pairs:

// Output: "evmWallet.sendTransaction.success transactionId=abc123 hash=0x456def"
Logger.smartWallet.info(LogEvents.evmSendTransactionSuccess, attributes: [
    "transactionId": transaction.id,
    "hash": transaction.onChain?.txId ?? ""
])

DataDog now receives formatted message strings only (with base service/platform attributes), which will be formatted into proper metadata on DataDog through a grok parser we'll implement for the mobile SDK

Custom LogLevel Enum

Replaced OSLogType with a custom LogLevel enum containing only the four levels from LoggerProvider:

let sdk = CrossmintSDK.shared(
    apiKey: apiKey,
    logLevel: .debug  // LogLevel (.debug, .info, .warn, .error)
)

The default level changed from .default to .error