Make about dialog show up as fullscreen on iOS

[ann0see]

Short description of changes
Fixes an UI overflow bug for the about dialog on iOS.

Related to: #3343
Now - with some potential device rotations the about dialog can be exited on Qt6:

CHANGELOG: SKIP

Context: Fixes an issue?

Related to: #3343

Does this change need documentation? What needs to be documented and how?

No
Status of this Pull Request

Ready

What is missing until this pull request can be merged?

Nothing

Checklist

• I've verified that this Pull Request follows the general code principles
• I tested my code and it does what I want
• My code follows the style guide
• I waited some time after this Pull Request was opened and all GitHub checks completed without errors.
• I've filled all the content above

[ann0see]

Not sure if you can test this. But please review.

[softins]

@ann0see could you explain what the problem behaviour without this fix is? I have just run an old Jamulus I have on my iPad (3.8.2beta1dev-75e4ad0c), and the About and Connect dialogs already show up as full screen with the OK or Connect buttons visible. Running iOS 16.7.10.

I can't remember how I got the above version of Jamulus onto my iPad. The icon is just a rounded white square with the word Jamulus in the middle.

[softins]

Or is the problem just on an iPhone instead? (I don't have one)

[ann0see]

The icon is just a rounded white square with the word Jamulus in the middle.

This is a version from the AppStore and not official in any way.

This issue only shows up on Qt6 based iOS builds.

[softins]

This issue only shows up on Qt6 based iOS builds.

OK fair enough. It looks sensible, so happy to approve.

[ann0see]

@pljones coumd you please also have a look at this?

[pljones]

Looks okay, too.

(Landscape only when I'm in Jamulus, moto g(9) power, Android 11)