rez-pip2 installs ruff incorrectly

Describe the bug here.

**Environment**
* OS : rocky9
* Rez version : 3.2.1
* Rez python version: 3.9.21

I installed `ruff` with `rez-pip2` and the `tools=['ruff']` line was not in the resulting `package.py` file. This was repeatable. That meant that the command `rez env ruff -- ruff` did nothing.

Using `rez-pip` to install it did work - the line was there and the package could be used.