Filter formats are consistently sorted

The config schema for filter formats now has the sort order defined.

When updating Drupal to a version with this change, the filter formats may be re-ordered in exported configuration YAML files but afterwards they will remain sorted consistently. (See commit cf2fd86fc for an example of such sort-order changes that may occur after a config export.)

Module and distribution maintainers should make sure their default configuration is sorted in order to minimize diffs when updating.