fix `xcodebuild` ci step

[michaelknoch]

Type of change: DX

Motivation (current vs expected behavior)

• update xcode on CI
• remove test which now fails on ios

Please check if the PR fulfills these requirements

• [ ] Self-review: I am confident this is the simplest and clearest way to achieve the expected behaviour
• [ ] There are no dependencies on other PRs or I have linked dependencies through Zenhub
• [ ] The commit messages are clean and understandable
• [ ] Tests for the changes have been added (for bug fixes / features)