Update on "[Executorch][llama] Allow custom sdpa op replacement pass to leverage attention mask"

Previously we assumed that the custom sdpa always does causal attention.
This diff adds option to this module swap pass to make custom sdpa leverage
attention mask instead of causal.

Differential Revision: [D73222736](https://our.internmc.facebook.com/intern/diff/D73222736/)

[ghstack-poisoned]

Author: kimishpatel

examples/models/llama/source_transformation/sdpa.py

@@ -47,7 +47,6 @@ def forward(
             torch._check_is_size(start_pos)
             torch._check(start_pos < self.max_context_len)
             seq_length = q.size(2)
-            # pyre-ignore: Incompatible parameter type [6]
             mask = mask.narrow(0, start_pos, seq_length)
         else:
             mask = mask[input_pos]