[CI Failure] Fix Gemma3 RoPE configuration for sliding attention layers (#29111)

Signed-off-by: Huamin Li <3ericli@gmail.com>
Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Co-authored-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Co-authored-by: Cyrus Leung <tlleungac@connect.ust.hk>

vllm/model_executor/models/gemma3.py

@@ -166,10 +166,12 @@ class Gemma3Attention(nn.Module):
         else:
             # Transformers v4 rope config.
             # Global attention. Use the values in config.json.
-            rope_parameters = config.rope_parameters.copy()
+            rope_parameters = config.rope_parameters
             # Local attention. Override the values in config.json.
             if self.is_sliding:
-                rope_parameters["rope_theta"] = config.rope_local_base_freq
+                rope_parameters = dict(
+                    rope_type="default", rope_theta=config.rope_local_base_freq
+                )
 
         self.rotary_emb = get_rope(
             self.head_dim,