BUG: `styler.to_latex` does hide rows after `hide_index([subset])`
### 

- [X] I have checked that this issue has not already been reported.

- [X] I have confirmed this bug exists on the [latest version](https://pandas.pydata.org/docs/whatsnew/index.html) of pandas.

- [X] I have confirmed this bug exists on the master branch of pandas.


### Reproducible Example

```python
>>> df = DataFrame([[1], [2]])
>>> print(df.style.hide_index([0]).to_latex())
\begin{tabular}{lr}
 & 0 \\
 \\
1 & 2 \\
\end{tabular}
```


### Issue Description

its the header cells that render as empty spaces creating an unwanted line. 

### Expected Behavior

no unwanted line.

### Installed Versions

master
