Description of the new feature/enhancement

#7667 introduces the TerminalSettingsModel by ripping out a large chunk of TerminalApp. All of the testing was thrown into LocalTests_SettingsModel. Moving them into a unit tests project like TermApp.UnitTests allows us to run these in CI.

About 20/33 tests are able to be moved into a UnitTests-like project with no modifications.
2/33 can be moved with minor modifications (see below).
The remaining 11/33 require a larger refactor (this issue tracks this).

Proposed technical implementation details (optional)

SettingsModelLocalTests::KeyBindingsTests

• All of these tests fail because they need to construct a KeyChord. KeyChord is in the TerminalControl namespace.

SettingsModelLocalTests::CommandTests

• TestResourceKeyName and TestLayerOnAutogeneratedName fail because they need access to the resource loader.

SettingsModelLocalTests::SerializationTests

• The tests below fail because they need to import defaults.json. Which results in hitting the two cases above.
  • TestReorderWithNullGuids
  • TestReorderingWithoutGuid
  • TestLayeringNameOnlyProfiles
  • TestExplodingNameOnlyProfiles
  • TestDontLayerGuidFromUserDefaults
  • ValidateKeybindingsWarnings
• TestCommandsAndKeybindings doesn't import defaults.json, but fails again because it hits the two cases above.
• The two tests that can be fixed fairly easily are ValidateLegacyGlobalsWarning and TestTrailingCommas. They don't really need a dependency on importing defaults.json.