GH-50348: [C++] Fix duplicate keys issue in KeyValueMetadata
#25586
| Job | Run time |
|---|---|
| 6m 5s | |
| 9m 26s | |
| 4m 22s | |
| 11m 33s | |
| 31m 26s |
KeyValueMetadata
#25586
| Job | Run time |
|---|---|
| 6m 5s | |
| 9m 26s | |
| 4m 22s | |
| 11m 33s | |
| 31m 26s |