Remove keyboard name from LAYOUT_moonlander

[3geek14]

This removes a build warning for moonlander:default.

Description

Rename LAYOUT_moonlander to LAYOUT in keyboards/moonlander/info.json. A small handful of keymaps exist in the repo, and two people referenced LAYOUT_moonlander in their user/ directories, so I updated uses in all of those files.

I tested building the default layout locally, and I'm expecting the CI to test everything else that's impacted by these files. I think this counts as a breaking change, which is why I'm targeting the develop branch.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[fauxpark]

Already done in #21898