Update on "Update eager runner to support AttentionSink"

This PR updates the eager runner to support AttentionSink.

It also fixes issues in the `chat_completion` function to properly handle the position id.

Differential Revision: [D66076486](https://our.internmc.facebook.com/intern/diff/D66076486/)

[ghstack-poisoned]

Author: helunwencser

examples/models/llama/source_transformation/attention_sink.py

@@ -266,7 +266,7 @@ def _replace_attention(
     for _, child_module in module._modules.items():
         if len(list(child_module.children())) > 0:  # pyre-ignore [16]
             _replace_attention(
-                module=child_module, # pyre-ignore [6]
+                module=child_module,  # pyre-ignore [6]
                 rope_with_attention_sink=rope_with_attention_sink,
                 sink_size=sink_size,
                 window_size=window_size,