Remove support for unused product interfaces (#24965)

We no longer rely on commands and hooks for products, so simplify this code.

server/channels/app/command.go

@@ -202,7 +202,7 @@ func (a *App) ExecuteCommand(c *request.Context, args *model.CommandArgs) (*mode
 
 	args.TriggerId = triggerId
 
-	// Plugins can override built in, custom, and product commands
+	// Plugins can override built in and custom commands
 	cmd, response, appErr := a.tryExecutePluginCommand(c, args)
 	if appErr != nil {
 		return nil, appErr
@@ -211,15 +211,6 @@ func (a *App) ExecuteCommand(c *request.Context, args *model.CommandArgs) (*mode
 		return a.HandleCommandResponse(c, cmd, args, response, true)
 	}
 
-	// Products can override built in and custom commands
-	cmd, response, appErr = a.tryExecuteProductCommand(c, args)
-	if appErr != nil {
-		return nil, appErr
-	} else if cmd != nil && response != nil {
-		response.TriggerId = clientTriggerId
-		return a.HandleCommandResponse(c, cmd, args, response, true)
-	}
-
 	// Custom commands can override built ins
 	cmd, response, appErr = a.tryExecuteCustomCommand(c, args, trigger, message)
 	if appErr != nil {