processor_id missing in exported facets exposed filter processor_configs

Problem/Motivation

In facets.views.schema.yml, processor_configs are described as each having a processor_id, yet this does not appear to be set in exported config (processor_id is totally absent).

This doesn't appear to cause any functional problems, but results in a missing schema error (core/lib/Drupal/Core/Config/Development/ConfigSchemaChecker.php:98) when attempting to utilize exported facets exposed filter config in a test.

processor_id appears to be necessary for the config system to understand what to expect for a given processor's settings. See the last line in facets.views.schema.yml:

type: plugin.plugin_configuration.facets_processor.[%parent.processor_id]

Steps to reproduce

1. Create a view with a facets exposed filter, configured to sort results by raw value (this sort setting will create a processor_configs sequence item in the config with a sort settings key set).
2. Export config for the view and see that sequence item has no processor_id.
3. Try to use this exported view config in a Drupal PHPUnit test and see ConfigSchemaChecker.php generate a missing schema error.
4. Manually add the missing processor_id: raw_value_widget_order into the sequence item and see that the missing schema error no longer presents.

Proposed resolution

TBD

Remaining tasks

Propose resolution, create MR, get review.

User interface changes

None.

API changes

None.

Data model changes

Required processor_id present in exported facets exposed filter config.