FullyValidatable configuration schema

Problem/Motivation

Stricter validation for config schema types is available →

Proposed resolution

• Review config schema and add validation constraints as possible.
• Fix existing, or add new tests to ensure it all validates.
• #config_target in ConfigFormBase: using validation constraints for editing simple config →
• SchemaCheckTrait::checkConfigSchema() now checks config schema strictly, including validation constraints →

Remaining tasks

• ✅ File an issue
• ➖ Addition/Change/Update/Fix
• ➖ Testing to ensure no regression
• ➖ Automated unit testing coverage
• ➖ Automated functional testing coverage
• ➖ Security
• ➖ Documentation
• ➖ Code review by maintainers
• ➖ Full testing and approval
• ➖ Credit contributors
• ➖ Release notes snippet
• ❌ Release

User interface changes

• N/A

API changes

• Invalid configuration changes with throw errors.

Data model changes

• N/A

Release notes snippet

• Link to this issue