bugfix(client): panic: send on closed channel

Fix:

    panic: send on closed channel

    goroutine 751872 [running]:
    github.com/andreykaipov/goobs.(*Client).writeEvent(...)
        /home/xaionaro/.gvm/pkgsets/go1.22.1/global/pkg/mod/github.com/andreykaipov/goobs@v1.4.1/client.go:363
    github.com/andreykaipov/goobs.(*Client).handleOpcodes(0xc0020c81a0, 0xc0013846c0)
        /home/xaionaro/.gvm/pkgsets/go1.22.1/global/pkg/mod/github.com/andreykaipov/goobs@v1.4.1/client.go:338 +0x5a5
    created by github.com/andreykaipov/goobs.(*Client).connect in goroutine 751658
        /home/xaionaro/.gvm/pkgsets/go1.22.1/global/pkg/mod/github.com/andreykaipov/goobs@v1.4.1/client.go:200

Essentially by design we should close a channel only after we finished
all possible writing to it. Thus moving the close statement of channel
IncomingResponses to be called right after the writer to the channel is
finished.

client.go

@@ -141,7 +141,6 @@ func (c *Client) markDisconnected() {
 		c.client.Log.Printf("[TRACE] Closing internal channels")
 		close(c.IncomingEvents)
 		close(c.client.Opcodes)
-		close(c.client.IncomingResponses)
 		close(c.client.Disconnected)
 	})
 }
@@ -210,7 +209,10 @@ func (c *Client) connect() (err error) {
 	authComplete := make(chan error)
 
 	go c.handleRawServerMessages(authComplete)
-	go c.handleOpcodes(authComplete)
+	go func() {
+		c.handleOpcodes(authComplete)
+		close(c.client.IncomingResponses)
+	}()
 
 	timer := time.NewTimer(c.client.ResponseTimeout * time.Millisecond)
 	defer timer.Stop()