Fixes#10426
## Summary
Fix rule B030 giving a false positive with Tuple operations like `+`.
[Playground](https://play.ruff.rs/17b086bc-cc43-40a7-b5bf-76d7d5fce78a)
```python
try:
...
except (ValueError,TypeError) + (EOFError,ArithmeticError):
...
```
## Reviewer notes
This is a little more convoluted than I was expecting -- because we can
have valid nested Tuples with operations done on them, the flattening
logic has become a bit more complex.
Shall I guard this behind --preview?
## Test Plan
Unit tested.