Fix the flutter project to build iOS app

At the beginning of the Flutter project, creating the iOS app worked well. But now I can no longer build it and create an iOS app.

Goals:
- Fix code to build an iOS app
--> Send me a build so I can check with my iOS device

- Make sure the build is up and running on my macOS
--> Access via Teamviewer

- Ensure that building the Android code is still possible.
--> Run on my Android Studio installed on Windows 10

Info
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