Theme check for settings keys inside presets and default

[aswamy]

What are you adding in this PR?

Fixes #624
Fixes #602

• Talked to @charlespwd and we won't be doing setting value check here

Shoutout to @AribaRajput for creating the initial PR to get this done quickly

• Closing this previous PR: https://github.com/Shopify/theme-tools/pull/620/files

What's next? Any followup issues?

• Found a few missing pieces of completion / hover / checks for schema that ill be tackling

How to test

NOTE: This check DOES NOT check if the theme block exists or not. That is the responsibility of another theme check. I have noticed a bug where if you have local blocks, and there are references to local blocks that dont exist within presets and default, no theme check error is thrown. I will fix that in a following PR.

Testing settings

1. Create preset/default settings

"settings": [{
    "type": "text",
    "id": "top-level-setting",
    "label": "TEXT"
  }
],

2. Create presets.[].settings and default.settings that has keys that match the settings.id defined above. Create some that don't. See error.

Testing preset/default block settings defined in local block

1. Create a local block with settings

"blocks": [
  {
    "type": "local-block",
    "name": "local block",
    "settings": [
      {
        "id": "local-setting",
        "type": "text",
        "label": "local setting"
      }
    ]
  }
]

3. Create presets.[].blocks.[].settings and default.blocks.[].settings that has keys that match the settings.id defined above. Create some that don't. See error.

Testing preset/default block settings defined in theme block

1. Create blocks that allows all theme blocks

"blocks": [
  {
    "type": "@theme"
  }
]

2. Create presets.[].blocks.[].settings and default.blocks.[].settings that has keys that match the settings.id defined in the block file being referenced. Create some that don't. See error.

Before you deploy

• I included a minor bump changeset
• My feature is backward compatible