Export kPayloadUrlMissingAttributePath to public header.

PiperOrigin-RevId: 575630771

Author: CEL Dev Team

eval/public/cel_value.cc

@@ -107,6 +107,9 @@ struct DebugStringVisitor {
 
 }  // namespace
 
+const absl::string_view kPayloadUrlMissingAttributePath =
+    cel::runtime_internal::kPayloadUrlMissingAttributePath;
+
 CelValue CelValue::CreateDuration(absl::Duration value) {
   if (value >= cel::runtime_internal::kDurationHigh ||
       value <= cel::runtime_internal::kDurationLow) {

eval/public/cel_value.h

@@ -684,6 +684,7 @@ ABSL_DEPRECATED("Prefer using the generic MemoryManager overload")
 CelValue CreateMissingAttributeError(google::protobuf::Arena* arena,
                                      absl::string_view missing_attribute_path);
 
+ABSL_CONST_INIT extern const absl::string_view kPayloadUrlMissingAttributePath;
 bool IsMissingAttributeError(const CelValue& value);
 
 // Returns error indicating the result of the function is unknown. This is used