feat: make dialogheaderfooter implement hascomponents

[ugur-vaadin]

Description

This PR makes DialogHeaderFooter implement HasComponents. This introduces the following APIs to both DialogHeader and DialogFooter:

• add(Collection<Component> components)
• add(String text)
• remove(Collection<Component> components)
• removeAll()
• addComponentAtIndex(int index, Component component
• addComponentAsFirst(Component component)

NOTE:
This might be breaking if dialog.getHeader().add(null); is used anywhere since it is going to be ambiguous after the refactoring. However, this is unlikely in practice since it is not supported and would throw a NullPonterException anyway.

Fixes #5735

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

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarCloud

[vaadin-bot]

This ticket/PR has been released with Vaadin 24.5.0.alpha8 and is also targeting the upcoming stable 24.5.0 version.