Update for XcodeProj with strongly typed settings

[kwridan]

Describe your changes

• Updates to xcdiff for compatibility with refactor: strongly typed values in BuildSettings and BuildFileSettings tuist/XcodeProj#903
• Build setting values are no longer type erased and instead can now either be a String or [String]
• This alleviates the need to casting values and throwing errors when dealing with build settings

Test Plan

• Verify CI passes

[codecov]

Codecov Report

Attention: Patch coverage is 88.13559% with 7 lines in your changes missing coverage. Please review.

Project coverage is 97.09%. Comparing base (c48fb45) to head (1b2ac14).
Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
...ffCore/Comparator/ResolvedSettingsComparator.swift	64.70%	6 Missing ⚠️
Sources/XCDiffCore/Library/PBX+Extensions.swift	95.83%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #145      +/-   ##
==========================================
+ Coverage   97.05%   97.09%   +0.04%     
==========================================
  Files          52       53       +1     
  Lines        2986     3034      +48     
==========================================
+ Hits         2898     2946      +48     
  Misses         88       88              

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