WandbLogger marks crashed runs as "Finished" instead of "Failed" in W&B sweeps

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### Bug description

When using W&B sweeps, a run that crashes via `sys.exit(0)` — or any other mechanism that causes Python to exit with code 0 — is incorrectly marked as **"Finished"** (green) in the W&B UI instead of **"Failed"**. This silently corrupts sweep results because a crashed run appears to have completed successfully.

`WandbLogger.finalize("failed")` previously did nothing (early return). Python's atexit handler then calls `wandb.finish()` with the process exit code, and since `sys.exit(0)` produces exit code 0, W&B interprets it as success.

**Expected:** The run is marked as "Failed".
**Actual:** The run is marked as "Finished".

I'll have a PR in a moment.

### What version are you seeing the problem on?

master

### Reproduced in studio

_No response_

### How to reproduce the bug

```python
Save the following as `crash_test.py`:

import sys
import torch
from lightning.pytorch import LightningModule, Trainer
from lightning.pytorch.loggers import WandbLogger
from torch.utils.data import DataLoader, TensorDataset

class CrashingModel(LightningModule):
def __init__(self):
super().__init__()
self.layer = torch.nn.Linear(1, 1)

def training_step(self, batch, batch_idx):
x, y = batch
loss = torch.nn.functional.mse_loss(self.layer(x), y)
self.log("train/loss", loss)
if batch_idx >= 2:
sys.exit(0)
return loss

def configure_optimizers(self):
return torch.optim.Adam(self.parameters())

trainer = Trainer(
max_epochs=3,
logger=WandbLogger(project="my_project"),
)
trainer.fit(CrashingModel(), DataLoader(TensorDataset(torch.randn(100, 1), torch.randn(100, 1))))

Save the following as `crash_test_sweep.yaml`:

program: crash_test.py
project: my_project
method: random
run_cap: 1
parameters:
learning_rate:
values: [0.001, 0.01, 0.1]

Then run:

wandb sweep crash_test_sweep.yaml
wandb agent

Observe that the run in the W&B sweep dashboard is marked as "Finished" (green) instead of "Failed".
```

### Error messages and logs

```
# Error messages and logs here please
```

### Environment

Current environment

* CUDA:
- GPU:
- NVIDIA GeForce RTX 3090
- NVIDIA GeForce RTX 3050
- available: True
- version: 12.8
* Lightning:
- lightning: 2.6.2
- lightning-utilities: 0.15.3
- pytorch-lightning: 2.6.2
- torch: 2.9.1
- torchmetrics: 1.8.2
- torchvision: 0.24.1
* System:
- OS: Linux
- architecture:
- 64bit
- ELF
- processor: x86_64
- python: 3.10.19
- release: 6.6.114.1-microsoft-standard-WSL2

### More info

_No response_

cc @ethanwharris @lantiga @morganmcg1 @borisdayma @scottire @parambharat

Start by tracing WandbLogger.finalize("failed") and the atexit path that calls wandb.finish(), then run the provided crash_test.py with crash_test_sweep.yaml through a W&B sweep. Done means a run ending through sys.exit(0) is shown as "Failed" rather than "Finished" in the sweep dashboard.

Written by the indexing model from the issue text.