Remove function extraction in ONNX rotary embedding (#2525)

Remove as_function attribute in ONNX rotary embedding fusion. (It is not
needed since it is a standard op.)

Signed-off-by: Ganesan Ramalingam <[email protected]>

Author: gramalingam

onnxscript/rewriter/onnx_fusions/_rotary_embedding.py

@@ -30,7 +30,7 @@ def _rotate_half_pattern(op, x, start1, end1, start2, end2):
 
 class RotaryEmbedding23Fusion(pattern.RewriteRuleClassBase):
     def __init__(self):
-        super().__init__(name="RotaryEmbedding23", as_function=True)
+        super().__init__(name="RotaryEmbedding23")
 
     def pattern(self, op, x, cos, sin, start1, end1, start2, end2):
         return x * cos + _rotate_half_pattern(op, x, start1, end1, start2, end2) * sin