Differentiate BF disabled error messages (#72248)

src/libraries/System.Runtime.Serialization.Formatters/src/Resources/Strings.resx

@@ -249,4 +249,7 @@
   <data name="BinaryFormatter_SerializationDisallowed" xml:space="preserve">
     <value>BinaryFormatter serialization and deserialization are disabled within this application. See https://aka.ms/binaryformatter for more information.</value>
   </data>
+  <data name="BinaryFormatter_SerializationNotSupportedOnThisPlatform" xml:space="preserve">
+    <value>BinaryFormatter serialization and deserialization are not supported on this platform. See https://aka.ms/binaryformatter for more information.</value>
+  </data>
 </root>

src/libraries/System.Runtime.Serialization.Formatters/src/System/Runtime/Serialization/Formatters/Binary/BinaryFormatter.PlatformNotSupported.cs

@@ -11,11 +11,11 @@ public sealed partial class BinaryFormatter : IFormatter
         [Obsolete(Obsoletions.BinaryFormatterMessage, DiagnosticId = Obsoletions.BinaryFormatterDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
         [RequiresUnreferencedCode(IFormatter.RequiresUnreferencedCodeMessage)]
         public object Deserialize(Stream serializationStream)
-            => throw new PlatformNotSupportedException(SR.BinaryFormatter_SerializationDisallowed);
+            => throw new PlatformNotSupportedException(SR.BinaryFormatter_SerializationNotSupportedOnThisPlatform);
 
         [Obsolete(Obsoletions.BinaryFormatterMessage, DiagnosticId = Obsoletions.BinaryFormatterDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
         [RequiresUnreferencedCode(IFormatter.RequiresUnreferencedCodeMessage)]
         public void Serialize(Stream serializationStream, object graph)
-            => throw new PlatformNotSupportedException(SR.BinaryFormatter_SerializationDisallowed);
+            => throw new PlatformNotSupportedException(SR.BinaryFormatter_SerializationNotSupportedOnThisPlatform);
     }
 }