Make connect dialog show up as fullscreen on iOS

[ann0see]

Short description of changes

Makes Connect dialog show up in full screen like Android if Qt6 is used. This fixes a severe UI issue on the Qt6 build of Jamulus for iOS which didn't allow to even tap the connect button. Now the connect dialog looks like this in dark mode: (broken styling but usable)

CHANGELOG: iOS: Fixed GUI issue preventing the connect dialog to show correctly

Context: Fixes an issue?

Related to issues mentioned in https://github.com/jamulussoftware/jamulus/issues/2711

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

No Status of this Pull Request Works based on local build. Didn't test IPA built by GitHub - but this still uses Qt5

What is missing until this pull request can be merged?

Nothing

Checklist

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

[ann0see]

The chat dialog probably also needs this.

[softins]

Looks like the Connect Dialog list entries also need some work to be compatible with a dark mode theme. I suspect those texts are set specifically to black instead of being left to default.

[ann0see]

@pljones Probably you can't test this. A review would still be good.

[pljones]

Might be the weekend before I can test it but it looks like it shouldn't cause problems.

[ann0see]

BlissOS Android test is ok.

[pljones]

OK, that appears to work for me (moto g(9) power, Android 11)