modes_spec, "yellow flash affects all signal groups" fails due to undocumented timeout value yellow_flash.

[sveitech]

This pull request introduced a new timeout value called yellow_flash: 1df95a6

The test in the title breaks if the field is not added to the config.

Consider having default values for new fields introduced to the config.

The documentation should also be updated. The field is not documented on https://rsmp-nordic.github.io/rsmp_validator/config/

[emiltin]

Hi,
I've added the helper Validator.get_config() to fetch a config in the PR #364.

If the config is missing it will stop with an error, telling you that it's missing.

I've updated (in the PR) all test to use the helper.

The helper also supports providing a default value, which will be used if the config is missing. but it's not currently used in any tests. In general I think it's better to avoid default values, and instead rely on an explicit config for the equipment you're testing.

I've updated the documentation on https://rsmp-nordic.github.io/rsmp_validator/config/ to include yellow_flash.

[emiltin]

Improved with #364.