forward fix

Summary:
Fix the test
```
buck test 'fbcode//mode/opt' fbcode//gen_ai/genie_projects/bonsai/tests/models:test_models -- --exact 'gen_ai/genie_projects/bonsai/tests/models:test_models - test_executorch_staticllama_models (gen_ai.genie_projects.bonsai.tests.models.test_model_def.TestModelDef)'
```

Reviewed By: psiddh, kirklandsign

Differential Revision: D79597179

Author: cccclai

examples/qualcomm/oss_scripts/llama/model/static_llama.py

@@ -70,7 +70,7 @@ def __init__(self, config: ModelArgs, output_new_cache_only=False):
 
         self.scale = float(self.head_dim) ** 0.5
 
-        if config.enable_r3:
+        if hasattr(config, "enable_r3") and config.enable_r3:
             self.register_buffer(
                 "r3_weight",
                 torch.tensor(
@@ -186,11 +186,11 @@ def forward_sha(
         ]
         for i in range(len(q)):
             q[i] = apply_rotary_emb_single(q[i], freqs_cos, freqs_sin)
-            if self.config.enable_r3:
+            if hasattr(self.config, "enable_r3") and self.config.enable_r3:
                 q[i] = torch.matmul(q[i], self.r3_weight.T)
         for i in range(len(k)):
             k[i] = apply_rotary_emb_single(k[i], freqs_cos, freqs_sin)
-            if self.config.enable_r3:
+            if hasattr(self.config, "enable_r3") and self.config.enable_r3:
                 k[i] = torch.matmul(k[i], self.r3_weight.T)
             k[i] = k[i].transpose(1, 2)