Make configuration schema fully validatable

Problem/Motivation

As a result of the change of the minimum supported core version to 10.3 in parent issue #3565209: [Meta] Drop support for Drupal 10.2 and below, it should now be possible to implement full validation of all of modules' configuration schema, introduced with change record: Stricter validation for config schema types is available, since version 10.3.0.

See the reports from Config Inspector:

Fix admin_toolbar.settings:

Fix validation of:

• menu_depth integer value with a Range constraint from 1 to 9 with a not in range error message.
• sticky_behavior string value with a Choice constraint with allowed values provided by an enum class callback.
• timeout integer value with a Choice constraint with allowed values provided by a final class callback returning a range of integers with a step.

Fix admin_toolbar_tools.settings:

Fix validation of max_bundle_number integer value with a Range constraint from 1 to 500 with a not in range error message.

Steps to reproduce

Proposed resolution

Fix the reported schema validation errors by adding validation constraints and the FullyValidatable property.

Examples of similar issues:

• #3379725: Make Block config entities fully validatable
• #3493946: Make configuration schema more validate-able
• #3508743: Fix schema errors and make the schema validatable
• #3508150: [META] Implement complete coverage of validatable config schema across plugins and entities
  (very good description of the API and data model changes)

Remaining tasks

User interface changes

API changes

Data model changes