finish aoco_fetch_row_version and appendonly_fetch_row_version

### Cloudberry Database version

_No response_

### What happened

```c++
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("feature not supported on appendoptimized relations")));
```

### What you think should happen instead

_No response_

### How to reproduce

-

### Operating System

centos7

### Anything else

_No response_

### Are you willing to submit PR?

- [ ] Yes, I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://cloudberrydb.org/community/coc).

Start by locating aoco_fetch_row_version and appendonly_fetch_row_version in the C sources and tracing their callers. The issue names no file, test, expected behavior, or reproduction, so clarify the intended row-version semantics first. Done should include defined behavior for both functions and coverage showing that the reported unsupported-feature error is addressed.

Written by the indexing model from the issue text.