[codemod][lowrisk] Remove unused exception parameter from caffe2/c10/mobile/CPUCachingAllocator.cpp (#116875)
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: kimishpatel, palmje
Pull Request resolved: https://github.com/pytorch/pytorch/pull/116875
Approved by: https://github.com/Skylion007
