Translate SwiftPM warning-control settings to Xcode build flags

Tuist now decodes and maps SwiftPM’s newer warning-control target build settings (treatAllWarnings, treatWarning, enableWarning) into the same OTHER_SWIFT_FLAGS / OTHER_CFLAGS / OTHER_CPLUSPLUSFLAGS lowering SwiftPM uses. Packages that use these APIs (such as swift-dependencies 1.13.0) load successfully and the package author’s per-warning behavior is preserved in the generated Xcode project. Linker warning-control settings and Swift enableWarning are still rejected.