Add Olmo3 AWQ mapping (#2063)

Huggingface: [Olmo 3
Collection](https://huggingface.co/collections/allenai/olmo-3)
Transformers:
[Olmo3DecoderLayer](https://github.com/huggingface/transformers/blob/main/src/transformers/models/olmo3/modeling_olmo3.py#L245-L275)

```python
class Olmo3DecoderLayer(GradientCheckpointingLayer):
    def forward(
        self,
        hidden_states: torch.Tensor,
        attention_mask: Optional[torch.Tensor] = None,
        position_ids: Optional[torch.LongTensor] = None,
        past_key_values: Optional[Cache] = None,
        use_cache: Optional[bool] = False,
        cache_position: Optional[torch.LongTensor] = None,
        position_embeddings: Optional[tuple[torch.Tensor, torch.Tensor]] = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> torch.Tensor:
        residual = hidden_states
        hidden_states, _ = self.self_attn(
            hidden_states=hidden_states,
            attention_mask=attention_mask,
            position_ids=position_ids,
            past_key_values=past_key_values,
            use_cache=use_cache,
            cache_position=cache_position,
            position_embeddings=position_embeddings,
            **kwargs,
        )
        hidden_states = self.post_attention_layernorm(hidden_states)
        hidden_states = residual + hidden_states

        # Fully Connected
        residual = hidden_states
        hidden_states = self.mlp(hidden_states)
        hidden_states = self.post_feedforward_layernorm(hidden_states)
        hidden_states = residual + hidden_states
        return hidden_states
```

Olmo3 uses the same decoder layer structure as EXAONE4. Related to
#2046.

### Test
Tested it with `examples/awq/llama_example.py` and modified
`MODEL_ID="allenai/Olmo-3-1125-32B"`.

with `_exaone4_mappings`
```
$ python3 examples/awq/llama_example.py 

========== SAMPLE GENERATION ==============
Hello my name is John and I am a 25 year old male. I have been having a problem with my left testicle for about 2 years now. I have been to the doctor and they have done a ultrasound and a CT scan and they have found nothing wrong. I have been having pain in my left testicle for about 2 years now. It is a dull pain that is always there. It is not a sharp pain. It is more of a dull ache. I have also been having a
==========================================
```

with `_default_mappings`
```
$ python3 examples/awq/llama_example.py 

========== SAMPLE GENERATION ==============
Hello my name is

  •
==========================================
```

Signed-off-by: lkm2835 <[email protected]>
Co-authored-by: Fynn Schmitt-Ulms <[email protected]>

Author: lkm2835

src/llmcompressor/modifiers/awq/mappings.py

@@ -166,6 +166,7 @@ class AWQMapping:
     "Llama4ForConditionalGeneration": _default_mappings,
     "Mistral3ForConditionalGeneration": _default_mappings,
     "MistralForCausalLM": _default_mappings,
+    "Olmo3ForCausalLM": _exaone4_mappings,
     "Phi3ForCausalLM": _phi_mappings,
     "Phi3VForCausalLM": _phi_mappings,
     "Qwen2ForCausalLM": _default_mappings,