The flutter icons removal have broken the iOS build

[teolemon]

What

[!] Error uploading ipa file:
| fastlane summary |
[Application Loader Error Output]: ERROR: [ContentDelivery.Uploader] Asset validation failed (90717) Invalid large app icon. The large app icon in the asset catalog in “Runner.app” can’t be transparent or contain an alpha channel. For details, visit: https://developer.apple.com/design/human-interface-guidelines/app-icons. (ID: 15b65b3e-cd36-481d-9f60-f99dc5afe302)
[Application Loader Error Output]: Error uploading '/var/folders/0g/hj_q_pzx65bbjnslxz9n0src0000gn/T/e992f994-05d5-441d-a452-1ad2a404c50f.ipa'.
+------+------------------------------+-------------+
[Application Loader Error Output]: Asset validation failed Invalid large app icon. The large app icon in the asset catalog in “Runner.app” can’t be transparent or contain an alpha channel. For details, visit: https://developer.apple.com/design/human-interface-guidelines/app-icons. (ID: 15b65b3e-cd36-481d-9f60-f99dc5afe302) (90717)

[monsieurtanuki]

Probably related to #5642.
One solution would be to roll back the content of AppIcon.appiconset.
Another would be to use an existing package to create the app icons, e.g. flutter_launcher_icons, in order to focus on Smoothie's added values.

[g123k]

This is just a one file change, there's no need for a dependency