olivero.settings config schema is wrong

Problem/Motivation

While working on test coverage for configuration schema improvements, I stumbled upon olivero.settings behaving weirdly.

turns out it's because its config schema is wrong, it does:

olivero.settings:
  type: theme_settings
  label: 'olivero settings'
  mapping:
    third_party_settings:
      type: mapping
      label: 'Third party settings'
      mapping:
        shortcut:
          type: mapping
          label: 'Shortcut'
          mapping:
            module_link:
              type: boolean
              label: 'Module Link'
    mobile_menu_all_widths:
      …
    site_branding_bg_color:
      …
    base_primary_color:
      …

but
theme_settings already has

theme_settings:
…
    third_party_settings:
      # Third party settings are always optional: they're an optional extension
      # point.
      requiredKey: false
      type: sequence
      label: 'Third party settings'
      sequence:
        type: theme_settings.third_party.[%key]

which combined with shortcut.schema.yml's

# Schema for theme settings.
theme_settings.third_party.shortcut:
  type: mapping
  label: 'Shortcut settings'
  mapping:
    module_link:
      type: boolean
      label: 'Add shortcut link'

Means that the entirety of that override should be removed.

Raised in #3111409-123: Add new Olivero frontend theme to Drupal 9.1 core as beta by @catch but it was never answered.

Steps to reproduce

Proposed resolution

Remove the pointless overrides.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet