For config with only two possible values, set the non-default value when that config is enabled

[raddevon]

This is a confusion I've experienced in the past, and it was recently called out in #317. Changing a boolean configuration value to the non-default value currently requires two steps: enabling the configuration and then setting the value. Since there are only two values, it seems like this UI could be simplified as a toggle that toggles the value directly without also forcing a user to turn that config on.

allow_user_specified_id in the screenshot below is a good example:

It's easy to miss that merely toggling on the toggle switch next to the config variable name has no actual effect since the default value is still set. The user must toggle the switch and also change the value. It makes sense in the context of a configuration with a string value or even an enum with multiple selections, but it's easier to miss on these boolean values.