Use LocalisableString in IHasText.

osu.Framework/Graphics/Sprites/IHasText.cs

···
 // Copyright (c) ppy Pty Ltd <[e-mail]>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Localisation;
+
 namespace osu.Framework.Graphics.Sprites
 {
     /// <summary>
···
     /// </summary>
     public interface IHasText : IDrawable
     {
-        string Text { get; set; }
+        LocalisableString Text { get; set; }
     }
 }

osu.Framework/Graphics/Sprites/SpriteText.cs

···
 
         private string displayedText => localisedText?.Value ?? text.ToString();
 
-        string IHasText.Text
-        {
-            get => Text.ToString();
-            set => Text = value;
-        }
-
         private FontUsage font = FontUsage.Default;
 
         /// <summary>