Fix start bot failure after switching reconginzer from Luis to None

[lei9444]

Description

Check error.

Task Item

Closes #1535

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code refactor (non-breaking change which improve code quality, clean up, add tests, etc)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Doc update (document update)

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have functionally tested my change

Screenshots

Please include screenshots or gifs if your PR include UX changes.

[boydc2014]

This did fixed the issue, but i wonder why we deal with luis config here, since we are not using luisRecongizer.

I'm not suggesting any immediate change here. It's totally OK that we want pass a placeholder as luisconfig to fit into the interface of 'start bot'.

Just want to make sure we leverage each issue & fix as a chance to review the code and the design. Like the similar question i posted here: #1215 (comment) . I hope you and @liweitian can spend some times to review the logic you guys implemented. See what we can improve.

Common practices we can use is

• Adding comments to the logic, when you add comments you will notice 'hard to describe what happend here", it's a signal of bad design
• Adding tests. When you find that, "testing one component requires 10 depenecenies" , it's also a signal.