Don't import torch.distributed when it's not available

This is a continuation of 217c47e but
for another module. This issue was spotted in nixpkgs (again) when
building lm-eval package that used a different path in transformers
library to reach the same failure.

Related: #35133

src/transformers/integrations/fsdp.py

@@ -26,6 +26,11 @@ def is_fsdp_managed_module(module: nn.Module) -> bool:
     if not is_torch_available():
         return False
 
+    import torch
+
+    if not torch.distributed.is_available():
+        return False
+
     import torch.distributed.fsdp
 
     return isinstance(module, torch.distributed.fsdp.FullyShardedDataParallel) or getattr(