[MM-52969] Revert "MM-51482_Create Apps Category and link to bots DM (#22918)" (#23647)

* Revert "MM-51482_Create Apps Category and link to bots DM (#22918)"

This reverts commit 1051925eec.

* Revert "MM-51711_Feature flag: APPS sidebar category (#22766)"

This reverts commit 9156205178.

server/channels/app/helper_test.go

@@ -253,12 +253,6 @@ func (th *TestHelper) InitBasic() *TestHelper {
 	return th
 }
 
-func (th *TestHelper) InitBasicWithAppsSidebarEnabled() *TestHelper {
-	th.App.Config().FeatureFlags.AppsSidebarCategory = true
-
-	return th.InitBasic()
-}
-
 func (th *TestHelper) DeleteBots() *TestHelper {
 	preexistingBots, _ := th.App.GetBots(&model.BotGetOptions{Page: 0, PerPage: 100})
 	for _, bot := range preexistingBots {