As rule binding could be null, we need to make sure to check that before checking for errors/warning (#2702)

…fore checking for any error/warnings.

src/libraries/Microsoft.PowerFx.Core/Binding/Binder.cs

@@ -3618,7 +3618,7 @@ namespace Microsoft.PowerFx.Core.Binding
                     // If the reference is to Control.Property and the rule for that Property is a constant,
                     // we need to mark the node as constant, and save the control info so we may look up the
                     // rule later.
-                    if (controlInfo?.GetRule(property.InvariantName) is { HasErrorsOrWarnings: false } rule && rule.Binding != null && rule.Binding.IsConstant(rule.Binding.Top))
+                    if (controlInfo?.GetRule(property.InvariantName) is IExternalRule rule && rule.Binding != null && !rule.HasErrorsOrWarnings && rule.Binding.IsConstant(rule.Binding.Top))
                     {
                         value = controlInfo;
                         isConstant = true;