fix: make the pbxproject fastlane compatible

[DimitarTachev]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• Tests for the changes are included.

What is the current behavior?

The disable_automatic_code_signing method in fastlane fails with: Seems to be a very old project file format - please open your project file in a more recent version of Xcode

What is the new behavior?

The project can be processed by the fastlane tools.