Make more icons required for iOS export per new Apple guidelines

[Calinou]

This closes #53631.

Is 167×167 (iPad Pro) and 180×180 (iPhone @3x) required now?

[bruvzg]

https://developer.apple.com/design/human-interface-guidelines/ios/icons-and-images/app-icon/

Seems like they are - 180x180 + 120x120 (for iPhone), 167x167 + 152x152 (for iPad) and 1024x1024 (App Store). 76x76 is for the old non-Retina iPads.

But you can target iPad or iPhone only, in this case some icons are optional.

Maybe we should make all icons optional and enable icons/generate_missing by default.

[Calinou]

Maybe we should make all icons optional and enable icons/generate_missing by default.

That sounds like a good idea. In fact, is there much of a point for disabling icons/generate_missing? If not, we could always enable it and rename the optional_icons section to icon_overrides. We'd only require setting one base icon (with the largest size).

[akien-mga]

Maybe we should make all icons optional and enable icons/generate_missing by default.

That sounds like a good idea. In fact, is there much of a point for disabling icons/generate_missing? If not, we could always enable it and rename the optional_icons section to icon_overrides. We'd only require setting one base icon (with the largest size).

Should we merge this PR, or implement this instead?

[akien-mga]

Superseded by #56861.