Fix duplicate XCFramework search paths causing crashes in large dependency graphs

This release fixes a crash that could occur when a static XCFramework was reached through multiple dependency paths in a large project graph. The generated build settings no longer accumulate duplicate SDK-conditioned FRAMEWORK_SEARCH_PATHS entries, and SDK-conditioned OTHER_SWIFT_FLAGS are deduplicated as well. Projects with diamond-shaped dependency graphs that link static Swift XCFrameworks behind dynamic XCFrameworks should now generate and build reliably again.