Add config schema for field.formatter settings

Thanks @sokru - we just made a change to the file, could you fix the conflicts please?

@Grevil could you check this afterwards please to be committed?

Rebased the MR.

I noticed a few issues and opened MR to address those https://git.drupalcode.org/project/spamspan/-/merge_requests/37

- At the moment the formatter settings with layout builder are not saved correctly and values under use_form are nested and not flattened. This happens because the form structure with layout builder is different than with field display overview form so the code in EmailSpamspanFormatter::validateSettingsForm is not correct.
- To solve this I removed this validate handler and use a #pre_render to display the use_form details while keeping the values flat.
This way it works on both and we do not need to know the entire form structure or make conditions.
- Added a test for the spamspan formatter and config schema tests for that and filter format
- Also centralized config schema under spamspan_plugin_settings so we can avoid repetition use it for the formatter and filter.

Attaching static patch for composer.

Thank you, @herved! This looks great!

Unsure, what to do with the Drupal requirement. Mentioned @joevagyok for this, what he thinks about dropping the D9 / D10.0.0 support in a minor / patch release.

Dropping D9 in a minor release, is fine. We should maintain Drupal releases up until their EOL. Based on the discussion in the MR, I would suggest adapting the core version constraints to ^10.1 || ^11 and making sure we have these respective builds in gitlab CI, which we do, by looking into the green pipeline.

grevil → changed the visibility of the branch 3452930-add-config-schema to hidden.

grevil → changed the visibility of the branch 3452930-config-schema-alt to hidden.

grevil → changed the visibility of the branch 3452930-config-schema-alt to active.

LGTM! Once the tests are green, we can merge this! :)

Thanks for your contribution @herved!

Automatically closed - issue fixed for 2 weeks with no activity.