Filter out duplicates when normalizing SettingValue

Author: fortmarek

Sources/XcodeGraph/Models/Settings.swift

@@ -22,8 +22,15 @@ public enum SettingValue: ExpressibleByStringInterpolation, ExpressibleByStringL
         case let .array(currentValue):
             if currentValue.count == 1 {
                 return .string(currentValue[0])
+            } else {
+                return .array(
+                    Array(
+                        Set(
+                            currentValue
+                        )
+                    )
+                )
             }
-            return self
         case .string:
             return self
         }