Theme check should warn you when you have `presets` and `default`

[aswamy]

Describe the bug If you have a presets and default in your section file's schema, you will see no theme check error, but when you run shopify theme dev, you will see an error saying the error.

Source

Expected behaviour

• Theme check should catch the error in VSCode
• Theme check in CLI should catch the error (i.e. running shopify theme check)

Actual behaviour

• No errors are shown until you run shopify theme dev