skip mandatory webhook topics during registration/unregistration

[nelsonwittwer]

Description

Friction with mandatory webhooks was identified in the shopify app gem. Since Mandatory webhooks aren't subscribed to via API, we need to gracefully skip them during registrations without breaking handlers.

This skips registration/unregistration for mandatory topics that are managed in the partner dashboard

How has this been tested?

Unit tests within this library. I've also created a new app using our ruby app template pointing to this branch and my fix to the app gem's branch to verify I could recreate webhook without error.

Checklist:

• My commit message follow the pattern described in here
• I have performed a self-review of my own code.
• I have added tests that prove my fix is effective or that my feature works.
• I have updated the project documentation.
• I have added a changelog line.

[paulomarg]

🔥

[mironov]

I think this breaks webhooks processing for mandatory webhooks.

shopify-api-ruby/lib/shopify_api/webhooks/registry.rb

Lines 179 to 183 in 82e4caf

	handler = @registry[request.topic]&.handler
	unless handler
	raise Errors::NoWebhookHandler, "No webhook handler found for topic: #{request.topic}."
	end

The @registry[request.topic] will be nil for mandatory webhooks because they were skipped in

shopify-api-ruby/lib/shopify_api/webhooks/registry.rb

Lines 25 to 27 in 82e4caf

	return if mandatory_webhook_topic?(topic)
	@registry[topic] = case delivery_method

[kirillplatonov]

Yep, I can confirm that too. Mandatory webhooks in v13.3.0 are broken. Please rollback this PR.

[nelsonwittwer]

Fixed with #1249

[kirillplatonov]

Thanks for the quick fix! 🙏