Add getitem support in graph builder. (#10910)

Summary:

Add call_getitem support in graph builder.

Differential Revision: D74817590

Author: hsharma35

backends/cadence/aot/graph_builder.py

@@ -96,6 +96,9 @@ def call_submodule(
     ) -> PassResult:
         return ExportPass().call(graph_module)
 
+    def call_getitem(self, value: ProxyValue, key:int, meta: Optional[NodeMetadata] = None) -> ProxyValue:
+        return super().call_getitem(value, key, meta or NodeMetadata({}))
+
     def _fx(
         self,
         kind: str,