[codemod][lowrisk] Remove unused exception parameter from caffe2/torch/csrc/jit/frontend/lexer.cpp (#116876)
Summary:
`-Wunused-exception-parameter` has identified an unused exception parameter. This diff removes it.
This:
```
try {
...
} catch (exception& e) {
// no use of e
}
```
should instead be written as
```
} catch (exception&) {
```
If the code compiles, this is safe to land.
Test Plan: Sandcastle
Reviewed By: palmje
Pull Request resolved: https://github.com/pytorch/pytorch/pull/116876
Approved by: https://github.com/Skylion007
