Error key contains a dot

Problem/Motivation

Errors related to config keys not supporting dots.
ie,
XMLSitemap Settings form:
Drupal\Core\Config\ConfigValueException: xmlsitemap.settings key contains a dot which is not supported. in Drupal\Core\Config\ConfigBase->validateKeys() (line 209 of core/lib/Drupal/Core/Config/ConfigBase.php).

PathAuto Settings form:
Drupal\Core\Config\ConfigValueException: pathauto.settings key contains a dot which is not supported. in Drupal\Core\Config\ConfigBase->validateKeys() (line 209 of core/lib/Drupal/Core/Config/ConfigBase.php).

Steps to reproduce

• Install a clean instance of Drupal
• Install and enable config enforce and config enforce devel
• Install and enable xmlsitemap and/or pathauto, try to config enforce and save their setting forms

Proposed resolution

After some debugging, the submission of those forms don't save the config used only for the original setting form, but instead takes all the values of the form state, and form state includes the config enforce values using as key probably the schema identifier of the module/form ---- in the examples above will be pathauto.settings and/or xmlsitemap.settings, causing the not allowed dots in configuration keys.

The resolution will be not to assume the the original config form will only handle their own values, so moving the config enforce values from the form state values is the approach.

- Include a submit handler to make sure to catch the form state values first.
- On config enforce or form submission, move the config enforce values out of the form state values.
- The original config form submission will process the data without the config enforce values.
- Return the config enforce values to the form state values before the config enforce submit process.

Probably there is a more elegant way, but this was a quick fix.

User interface changes

none

API changes

none

Data model changes

none