feat: Add HasStyle interface to AppLayout #2854

[krissvaa]

Description

feat: Add HasStyle interface to App layout component

Some Flow components currently didn't implement the HasStyle interface, making it awkward to apply CSS classnames and inline styles to them.

This code change adds this functionality.

Fixes #2853

Type of change

• Bugfix
• Feature

Checklist

• I have read the contribution guide: https://vaadin.com/docs-beta/latest/guide/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.

Additional for Feature type of change

• Enhancement / new feature was discussed in a corresponding GitHub issue and Acceptance Criteria were created.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
839 Code Smells

No Coverage information
0.0% Duplication

[vaadin-bot]

This ticket/PR has been released with Vaadin 23.1.0.alpha1 and is also targeting the upcoming stable 23.1.0 version.