[MM-47538] Pass handler functions directly while creating API endpoints (#21441)

* Pass handler functions directly without permission check middlewares

* Create necessary handlers in api4/group_local.go

* Refactor GetGroupsByTeam, GetGroupsByChannel to a common function for local and API

api4/group_local.go

@@ -3,7 +3,39 @@
 
 package api4
 
+import (
+	"net/http"
+)
+
 func (api *API) InitGroupLocal() {
-	api.BaseRoutes.Channels.Handle("/{channel_id:[A-Za-z0-9]+}/groups", api.APILocal(getGroupsByChannel)).Methods("GET")
-	api.BaseRoutes.Teams.Handle("/{team_id:[A-Za-z0-9]+}/groups", api.APILocal(getGroupsByTeam)).Methods("GET")
+	api.BaseRoutes.Channels.Handle("/{channel_id:[A-Za-z0-9]+}/groups", api.APILocal(getGroupsByChannelLocal)).Methods("GET")
+	api.BaseRoutes.Teams.Handle("/{team_id:[A-Za-z0-9]+}/groups", api.APILocal(getGroupsByTeamLocal)).Methods("GET")
+}
+
+func getGroupsByChannelLocal(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireChannelId()
+	if c.Err != nil {
+		return
+	}
+	b, appErr := getGroupsByChannelCommon(c, r)
+	if appErr != nil {
+		c.Err = appErr
+		return
+	}
+
+	w.Write(b)
+}
+
+func getGroupsByTeamLocal(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireTeamId()
+	if c.Err != nil {
+		return
+	}
+	b, appError := getGroupsByTeamCommon(c, r)
+	if appError != nil {
+		c.Err = appError
+		return
+	}
+
+	w.Write(b)
 }