Fix ContentType

src/Web/Common/BlobStorage/ContentTypes.cs

@@ -7,7 +7,7 @@ public static class ContentTypes
     private const string ImagePng = "image/png";
     private const string ImageJpeg = "image/jpeg";
     private const string ImageJpg = "image/jpg";
-    private static string TextHtml = "text/html";
+    private const string TextHtml = "text/html";
 
     private static readonly HashSet<string> AllowedContentTypes = [ImagePng, ImageJpeg, ImageJpg, TextHtml];