Hide "Import files" button in settings on iOS

[frenzibyte]

Following ppy/osu-framework#6445, and restating the comment in the commit, the screen does not look appropriate on iOS with system file selection implemented (initial testing shows it to be severely broken), and functionality is already provided by opening such files externally, so I don't think it's worth the effort to try and fix this rather than just omit it from iOS.

[peppy]

Hmm, in theory this button could show the new file selector you made and allow importing files, no?

[frenzibyte]

The button opens up a new screen-based file import interface with extra functionalities that I don't see any benefit to have it work on iOS.

[frenzibyte]

To further explain what I mean, this is how the experience looks like without any osu!-side changes:

ScreenRecording_12-08-2024.02-00-25_1.mov

Multiple decisions can be taken here:

• Make the "Import files" button not push a screen when a system file selector is provided.
• Fix the file import screen to work with system file selector, i.e. make the file import screen be aware when the system file selector has been cancelled and have it exit itself.

But I took a step back and saw that the functionality provided by this button is unnecessary on iOS, and I'm pretty sure the button was only added because iOS/Android lacked ability to import files externally via file association. So I thought to myself why not just remove this button on iOS and call it a day, it's not useful enough to spend time making it not look broken.

[peppy]

Either of those options sound good. The former is probably the best.

[frenzibyte]

Sure, I thought it's not worth the effort but I can do it.