selfattention block: Remove the fc linear layer if it is not used

Signed-off-by: John Zielke <j.l.zielke@gmail.com>

Author: johnzielke

monai/networks/blocks/selfattention.py

@@ -106,7 +106,11 @@ def __init__(
 
         self.num_heads = num_heads
         self.hidden_input_size = hidden_input_size if hidden_input_size else hidden_size
-        self.out_proj = nn.Linear(self.inner_dim, self.hidden_input_size)
+        self.out_proj: nn.Module
+        if include_fc:
+            self.out_proj = nn.Linear(self.inner_dim, self.hidden_input_size)
+        else:
+            self.out_proj = nn.Identity()
 
         self.qkv: Union[nn.Linear, nn.Identity]
         self.to_q: Union[nn.Linear, nn.Identity]