refactor: open date picker overlay on element focus in fullscreen

[DiegoCardoso]

Description

This change overrides the focus method to change how focus is handled when the element is in fullscreen mode and it's focused. This is needed to avoid the element being immediately removed by the Grid Pro when the user is on a device with small viewport. The element receives focus, but the _onFocus listener has a similar detection, which removes the focus from the input element, which causes the component to be removed from the cell when used as a custom editor.

Part of #9158

Type of change

Refactor

[DiegoCardoso]

I was able to refactor the DatePickerObserver class used by the field highlighter to fix the current test failure. But these changes are causing this other test to fail, that I am unsure whether is still relevant or an indication that the changes introduced in this PR might be problematic for the field highlighter.

As this PR prevents the input element from being focused, calling focus on the date picker will behave in the same way as the user clicking on the host element. So, there's no blur at the moment the focus method is called. With the changes I have locally, the vaadin-highlight-show is triggered when the focus is called. So there would be a slight change in behavior for this case.

WDYT, @web-padawan?

[web-padawan]

But these changes are causing this other test to fail, that I am unsure whether is still relevant

IMO it makes sense to remove that test in this case. The behavior change sounds good to me.

[sonarqubecloud]

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

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