[Fastlane.swift] fix Unexpected duplicate tasks error message in Fastlane Swift

[mollyIV]

Checklist

• I've run bundle exec rspec from the root directory to see all new and existing tests pass
• I've followed the fastlane code style and run bundle exec rubocop -a to ensure the code style is valid
• I see several green ci/circleci builds in the "All checks have passed" section of my PR (connect CircleCI to GitHub if not)
• I've read the Contribution Guidelines
• I've updated the documentation if necessary.
• I've added or updated relevant unit tests.

Motivation and Context

Resolves #20104

Description

As mentioned in #20104 (comment), the issue is about having two build phases that copy FastlaneRunner target.

To fix this problem, we added additional logic to check if Copy Files build phase already contains FastlaneRunner target. If it does, we will not add redundant FastlaneRunnerCopySigned build phase.

The change is additive to be extra safe to not break anything. However, it'd be nice to understand the reasoning behind original decision in favour of "FastlaneRunnerCopySigned" introduction and clean up / adjust code based accordingly.

Testing Steps

Steps to test:

• initialize fastlane Swift in iOS project via fastlane init swift
• execute bundle exec fastlane customLane
• answer YES to "Should we try to upgrade just your FastlaneSwiftRunner project?" question
• validate if there's no error anymore
• open FastlaneSwiftRunner and check if there's no "FastlaneRunnerCopySigned" phase in Build Phases

Tested on Xcode 15, macOS Sonoma 14.0.

Thank you 🙇

[joshdholtz]

Heyyy, its good to see you again 😊

This looks good to me! I don't know the history of this file. I believe that would be @taquitos if he is able to look at it 🤷‍♂️

[lacostej]

Looks good to me as well :) Thanks for the PR!