Update KeyValueMetadata::Delete IndexError message

Co-authored-by: Antoine Pitrou <pitrou@free.fr>

Author: OmBiradar

cpp/src/arrow/util/key_value_metadata.cc

@@ -101,18 +101,9 @@ Result<std::string> KeyValueMetadata::Get(std::string_view key) const {
 
 Status KeyValueMetadata::Delete(int64_t index) {
   if (ARROW_PREDICT_FALSE(index < 0 || std::cmp_greater_equal(index, values_.size()))) {
-    const size_t n = keys_.size();
-    if (n == 0LL) {
-      return Status::IndexError("KeyValueMetadata::Delete: index ", std::to_string(index),
-                                " is out of bounds for metadata "
-                                "of size ",
-                                std::to_string(n), ". Metadata is empty.");
-    }
-    return Status::IndexError("KeyValueMetadata::Delete: index ", std::to_string(index),
+    return Status::IndexError("KeyValueMetadata::Delete: index ", index,
                               " is out of bounds for metadata "
-                              "of size ",
-                              std::to_string(n), " (valid range: [0, ",
-                              std::to_string(n - 1), "])");
+                              "of size ", keys_.size());
   }
   keys_.erase(keys_.begin() + index);
   values_.erase(values_.begin() + index);