feat: add handler for WebSocket peer closed event

[Twist96]

Add missing case for .peerClosed event in WebSocket delegate to ensure complete event handling coverage.

Description

• Added missing case handler for .peerClosed WebSocket event in SolanaSocket's WebSocketDelegate implementation to ensure comprehensive event handling and proper debug logging support
• https://github.com/Twist96/Solana.Swift/blob/f907882a076db77ccbc2676791114601044cc00d/Sources/Solana/Networking/Socket/SolanaSocket.swift#L144
• https://github.com/Twist96/Solana.Swift/blob/f907882a076db77ccbc2676791114601044cc00d/Sources/Solana/Networking/Socket/SolanaSocket.swift#L170

Work Completed

• Implemented .peerClosed case in the didReceive event handler switch statement
• Added corresponding debug logging support for the peer closed event in the log function
• Maintained consistent code style and debug logging pattern with existing implementation

Testing

• Non necessary.