fix: add manual validation property to custom field

[ugur-vaadin]

Description

This PR sets manualValidation property on the CustomField in order to keep the validation in sync. Based on the approach in the PR #6792.

Possibly fixes other issues around CustomField validation.

Fixes #7483

Type of change

• Bugfix
• Feature

Checklist

• I have read the contribution guide: https://vaadin.com/docs/latest/contributing/overview
• I have added a description following the guideline.
• The issue is created in the corresponding repository and I have referenced it.
• I have added tests to ensure my change is effective and works as intended.
• New and existing tests are passing locally with my change.
• I have performed self-review and corrected misspellings.

[web-padawan]

I suppose we can now also remove FieldValidationUtil from CustomField added in #3277.
Also it would be good to have some IT that would verify the improvement.

[ugur-vaadin]

I suppose we can now also remove FieldValidationUtil from CustomField added in #3277. Also it would be good to have some IT that would verify the improvement.

Removed FieldValidationUtil and added an IT.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud