Revert "[MM-37984] Allow Desktop App to authenticate via external providers outside of the app on supported servers (#23795)" (#24039)

This reverts commit abdf4e58c3.

server/channels/api4/handlers.go

@@ -9,8 +9,6 @@ import (
 	"github.com/mattermost/gziphandler"
 
 	"github.com/mattermost/mattermost/server/public/model"
-	"github.com/mattermost/mattermost/server/public/shared/mlog"
-	"github.com/mattermost/mattermost/server/v8/channels/app"
 	"github.com/mattermost/mattermost/server/v8/channels/web"
 )
 
@@ -202,17 +200,6 @@ func (api *API) APILocal(h handlerFunc) http.Handler {
 	return handler
 }
 
-func (api *API) RateLimitedHandler(apiHandler http.Handler, settings model.RateLimitSettings) http.Handler {
-	settings.SetDefaults()
-
-	rateLimiter, err := app.NewRateLimiter(&settings, []string{})
-	if err != nil {
-		mlog.Error("getRateLimitedHandler", mlog.Err(err))
-		return nil
-	}
-	return rateLimiter.RateLimitHandler(apiHandler)
-}
-
 func requireLicense(c *Context) *model.AppError {
 	if c.App.Channels().License() == nil {
 		err := model.NewAppError("", "api.license_error", nil, "", http.StatusNotImplemented)