[MM-31359] remove duplicated error logs (#16583)

* remove duplicated error logs

* reflect review comments

* add context

* add error details

api4/websocket.go

@@ -7,7 +7,6 @@ import (
 	"net/http"
 
 	"github.com/gorilla/websocket"
-	"github.com/mattermost/mattermost-server/v5/mlog"
 	"github.com/mattermost/mattermost-server/v5/model"
 )
 
@@ -25,7 +24,6 @@ func connectWebSocket(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	ws, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
-		mlog.Error("websocket connect err.", mlog.Err(err))
 		c.Err = model.NewAppError("connect", "api.web_socket.connect.upgrade.app_error", nil, "", http.StatusInternalServerError)
 		return
 	}