WebBrokerAPI: Fix: Avoid closing shared channels in WebBrokerApi closeConnection to prevent panics

Summary

In event-gateway/gateway-runtime/internal/connectors/receiver/websocket/broker_api_connector.go, the closeConnection method currently closes the conn.inbound and conn.outbound channels directly during teardown. This can cause panics when other goroutines (e.g., the broker consumer callback) are still attempting to send to these channels concurrently.

Problem

close(conn.inbound)
close(conn.outbound)

Since the broker callback goroutine may still be writing to conn.outbound after closeConnection is called, closing the channel here can result in a "send on closed channel" panic.

Proposed Fix

• Remove the close(conn.inbound) and close(conn.outbound) calls from closeConnection.
• Rely on context cancellation (already present via conn.cancel()) and consumer stop as the shutdown signal.
• Ensure goroutines that own/read these channels are responsible for closing them when appropriate, after observing context cancellation.
• Document that conn.outbound is not closed by teardown to avoid races with broker callback sends.

References

• PR: https://github.com/wso2/api-platform/pull/1954#discussion_r3239562637
• Related: https://github.com/wso2/api-platform/pull/1944

Requested by @senthuran16