[train] update quick start timeout (#47732)

The time is spent mostly on downloading the dataset to disk, and
training times out after 15 seconds.

Bumping to 300 seconds.

Signed-off-by: Matthew Deng <matt@anyscale.com>
Co-authored-by: Hongpeng Guo <hpguo@anyscale.com>

python/ray/train/BUILD

@@ -118,7 +118,7 @@ py_test(
 
 py_test(
     name = "torch_quick_start",
-    size = "small",
+    size = "medium",
     main = "examples/pytorch/torch_quick_start.py",
     srcs = ["examples/pytorch/torch_quick_start.py"],
     tags = ["team:ml", "exclusive"],