Merged PR 251300: Made MSColors and MSFonts classes instead of structs and added attributes to support Objective-C

Made MSColors and MSFonts classes instead of structs and added attributes to support Objective-C

Related work items: #705414

OfficeUIFabric/Core/Colors.swift

@@ -5,7 +5,8 @@
 
 // MARK: MSColors
 
-public struct MSColors {
+@objcMembers
+public final class MSColors: NSObject {
     // MARK: Primary
 
     /// #0078D4
@@ -186,6 +187,10 @@ public struct MSColors {
         public static let background: UIColor = white
         public static let backgroundSelected: UIColor = backgroundGray
     }
+
+    private override init() {
+        super.init()
+    }
 }
 
 // MARK: - MSTextColorStyle

OfficeUIFabric/Core/Fonts.swift

@@ -3,7 +3,8 @@
 //  Licensed under the MIT License.
 //
 
-public struct MSFonts {
+@objcMembers
+public final class MSFonts: NSObject {
     /// Semibold 28pt
     public static var title1: UIFont { return UIFont.preferredFont(forTextStyle: .title1).withWeight(.semibold) }
     /// Semibold 22pt
@@ -20,6 +21,10 @@ public struct MSFonts {
     public static var caption1: UIFont { return .preferredFont(forTextStyle: .caption1) }
     /// Regular 11pt
     public static var caption2: UIFont { return .preferredFont(forTextStyle: .caption2) }
+
+    private override init() {
+        super.init()
+    }
 }
 
 @objc public enum MSTextStyle: Int, CaseIterable {