Reduce code duplicate

Please find a patch which rework the validateForm(), submitForm() and layout_builder_component_attributes_preprocess_block().

It is more complex to adapt the buildForm() as some labels and description are different per element type. Reworking this may reduce the code duplication but will make it harder to understand and maintain.

The last submitted patch, 2: reduce_code_duplicate-3349365-2.patch, failed testing. View results →
- codesniffer_fixes.patch Interdiff of automated coding standards fixes only.

@vbouchet - Thanks for the patch!

I created a patch in the above issue.

Hiding the patch that causes the regression.

The regression is being worked in #3388042: Regression: block attribute classes end up on block title as well → .

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