[perflint] Implement try-except-in-loop (PERF203) (#5166)

## Summary

Implements PERF203 from #4789, which throws if a `try/except` block is
inside of a loop. Not sure if we want to extend the diagnostic to the
`except` as well, but I thought that that may get a little messy. We may
also want to just throw on the word `try` - open to suggestions though.

## Test Plan
`cargo test`

scripts/pyproject.toml

@@ -18,6 +18,7 @@ ignore = [
   "G",     # flake8-logging
   "T",     # flake8-print
   "FBT",   # flake8-boolean-trap
+  "PERF",  # perflint
 ]
 
 [tool.ruff.isort]