Respect non-config settings on synth drivers

[LeonarddeR]

Link to issue number:

None

Summary of the issue:

A synth driver inherrits from autoSettingsUtils.autoSettings.AutoSettings but overrides its loadSettings method to work around changing the voice. However, that override doesn't respect settings that aren't saved in config, like the parent class does.

Description of user facing changes

None

Description of development approach

Ensure that a synth doesn't try to get a setting from config that's not a setting stored in config.

Testing strategy:

Tested with an add-on that had synth settings with useConfig set to False. The synth was able to load again.

Known issues with pull request:

None

Change log entries:

For Developers

• It is possible to set useConfig to False on supported settings for a synthesizer driver.

Code Review Checklist:

• Pull Request description:
  • description is up to date
  • change log entries
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• API is compatible with existing add-ons.
• Documentation:
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• Security precautions taken.