Move request package into public/shared folder (#24420)

* move request package to public/shared

* updated app-layers

* update app layer

* remove original package location

server/channels/api4/command_test.go

@@ -17,7 +17,7 @@ import (
 
 	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
-	"github.com/mattermost/mattermost/server/v8/channels/app/request"
+	"github.com/mattermost/mattermost/server/public/shared/request"
 )
 
 func TestCreateCommand(t *testing.T) {