docs: typo fixes in notebook

Author: okunator

examples/pannuke_nuclei_segmentation_stardist.ipynb

@@ -226,7 +226,6 @@
     "import torch\n",
     "import torch.nn as nn\n",
     "import torch.optim as optim\n",
-    "import torchmetrics\n",
     "\n",
     "\n",
     "class SegmentationExperiment(pl.LightningModule):\n",
@@ -236,7 +235,6 @@
     "        multitask_loss: Dict[str, nn.Module],\n",
     "        optimizer: optim.Optimizer,\n",
     "        scheduler: optim.lr_scheduler._LRScheduler,\n",
-    "        branch_metrics: Optional[Dict[str, List[torchmetrics.Metric]]] = None,\n",
     "        optimizer_kwargs: Optional[Dict[str, float]] = None,\n",
     "        scheduler_kwargs: Optional[Dict[str, float]] = None,\n",
     "        **kwargs,\n",
@@ -253,7 +251,6 @@
     "        self.optimizer_kwargs = optimizer_kwargs or {}\n",
     "        self.scheduler_kwargs = scheduler_kwargs or {}\n",
     "\n",
-    "        self.branch_metrics = branch_metrics\n",
     "        self.criterion = multitask_loss\n",
     "\n",
     "        self._validate_branch_args()\n",