Copying result with ProxyResultSetMethod on it results in failure

Copy fails with

```
DBIx::Class::ResultSource::columns_info(): No such column 'id_plus_one' on source 'Gnarly'
```

[15:12:55] <moltar>	 frew: when trying to ->copy a $result which has ::ProxyResultSetMethod on it, it stuffs the data into _column_data and when trying to copy it fails with No such column 'archive_count' on source ...
[15:13:16] <@frew>	 ah I bet it does
[15:13:25] <@frew>	 moltar: get me a test and I'll take care of it
[15:13:29] <@frew>	 otherwise it might be a day or two
[15:13:42] <moltar>	 ok lets see what i can do :)
[15:13:56] <@frew>	 hmmm
[15:14:13] <@frew>	 I bet even w/e ProxyResultSetMethod it can still happen if you prefetch
[15:14:36] <@frew>	 though ofc ProxyResultSetMethod could fix it.