After using math font package in tex_template of ManinGL， the TexText cannot displayed correctly，

### Describe the bug

After using math font package in tex_template of ManinGL，such as “\usepackage{fourier}”,
once I use the latex command that involves changing words size， the TexText will be displayed incorrectly，
such as “$x^{y}$ ”, “ $x_{y}$”, ”{\small $x$}+$y$".

I inspect the (.svg) file it outputs.
the result is correct.
So I think it is a displayed bug
**Code**:

**Wrong display or Error traceback**:

### Additional context