Lazy load torch (#1027)

* lazy torch import

* use @Zethson implementation

* remove import from future

* add again from __future__ import annotations

Author: quentinblampey

src/spatialdata/dataloader/__init__.py

@@ -1,4 +1,21 @@
-try:
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+import spatialdata
+
+if TYPE_CHECKING:
     from spatialdata.dataloader.datasets import ImageTilesDataset
-except ImportError:
-    ImageTilesDataset = None  # type: ignore[assignment, misc]
+
+__all__ = [
+    "ImageTilesDataset",
+]
+
+
+def __getattr__(attr_name: str) -> ImageTilesDataset | Any:
+    if attr_name == "ImageTilesDataset":
+        from spatialdata.dataloader.datasets import ImageTilesDataset
+
+        return ImageTilesDataset
+
+    return getattr(spatialdata.dataloader, attr_name)