Incorrect import path for AzureAIChatCompletionsModel in the _init_chat_model_helper call

### Checked other resources

- [x] I added a very descriptive title to this issue.
- [x] I searched the LangChain documentation with the integrated search.
- [x] I used the GitHub search to find a similar question and didn't find it.
- [x] I am sure that this is a bug in LangChain rather than my code.
- [x] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

### Example Code


```python
  from langchain.chat_models import init_chat_model

  chat_model = init_chat_model("azure_ai:gpt-4o-mini")
```

### Error Message and Stack Trace (if applicable)

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".venv/lib/python3.12/site-packages/langchain/chat_models/base.py", line 326, in init_chat_model
    return _init_chat_model_helper(
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File ".venv/lib/python3.12/site-packages/langchain/chat_models/base.py", line 362, in _init_chat_model_helper
    from langchain_azure_ai import AzureAIChatCompletionsModel
ImportError: cannot import name 'AzureAIChatCompletionsModel' from 'langchain_azure_ai' (.venv/lib/python3.12/site-packages/langchain_azure_ai/__init__.py)

### Description

Calling init_chat_model("azure_ai:gpt-4o-mini") results in an import error due to an incorrect import statement inside _init_chat_model_helper.

The correct import should be:

```python
from langchain_azure_ai.chat_models import AzureAIChatCompletionsModel
```

### System Info

System Information
------------------
> OS:  Linux
> OS Version:  #57-Ubuntu SMP PREEMPT_DYNAMIC Wed Feb 12 23:42:21 UTC 2025
> Python Version:  3.12.3 (main, Feb  4 2025, 14:48:35) [GCC 13.3.0]

Package Information
-------------------
> langchain_core: 0.3.45
> langchain: 0.3.21
> langchain_community: 0.3.20
> langsmith: 0.3.16
> langchain_azure_ai: 0.1.2
> langchain_chroma: 0.2.2
> langchain_google_genai: 2.1.0
> langchain_openai: 0.3.9
> langchain_text_splitters: 0.3.7
> langgraph_sdk: 0.1.57

Optional packages not installed
-------------------------------
> langserve

Other Dependencies
------------------
> aiohttp: 3.11.14
> aiohttp<4.0.0,>=3.8.3: Installed. No version info available.
> async-timeout<5.0.0,>=4.0.0;: Installed. No version info available.
> azure-ai-inference[opentelemetry]: Installed. No version info available.
> azure-core: 1.32.0
> azure-cosmos: 4.9.0
> azure-identity: 1.21.0
> azure-monitor-opentelemetry: Installed. No version info available.
> chromadb!=0.5.10,!=0.5.11,!=0.5.12,!=0.5.4,!=0.5.5,!=0.5.7,!=0.5.9,<0.7.0,>=0.4.0: Installed. No version info available.
> dataclasses-json<0.7,>=0.5.7: Installed. No version info available.
> filetype: 1.2.0
> google-ai-generativelanguage: 0.6.17
> httpx: 0.28.1
> httpx-sse<1.0.0,>=0.4.0: Installed. No version info available.
> jsonpatch<2.0,>=1.33: Installed. No version info available.
> langchain-anthropic;: Installed. No version info available.
> langchain-aws;: Installed. No version info available.
> langchain-azure-ai;: Installed. No version info available.
> langchain-cohere;: Installed. No version info available.
> langchain-community;: Installed. No version info available.
> langchain-core!=0.3.0,!=0.3.1,!=0.3.10,!=0.3.11,!=0.3.12,!=0.3.13,!=0.3.14,!=0.3.2,!=0.3.3,!=0.3.4,!=0.3.5,!=0.3.6,!=0.3.7,!=0.3.8,!=0.3.9,<0.4.0,>=0.2.43: Installed. No version info available.
> langchain-core<1.0.0,>=0.3.45: Installed. No version info available.
> langchain-deepseek;: Installed. No version info available.
> langchain-fireworks;: Installed. No version info available.
> langchain-google-genai;: Installed. No version info available.
> langchain-google-vertexai;: Installed. No version info available.
> langchain-groq;: Installed. No version info available.
> langchain-huggingface;: Installed. No version info available.
> langchain-mistralai;: Installed. No version info available.
> langchain-ollama;: Installed. No version info available.
> langchain-openai;: Installed. No version info available.
> langchain-text-splitters<1.0.0,>=0.3.7: Installed. No version info available.
> langchain-together;: Installed. No version info available.
> langchain-xai;: Installed. No version info available.
> langchain<1.0.0,>=0.3.21: Installed. No version info available.
> langsmith-pyo3: Installed. No version info available.
> langsmith<0.4,>=0.1.125: Installed. No version info available.
> langsmith<0.4,>=0.1.17: Installed. No version info available.
> numpy: 1.26.4
> numpy<2.0.0,>=1.22.4;: Installed. No version info available.
> numpy<2.0.0,>=1.26.2;: Installed. No version info available.
> numpy<3,>=1.26.2: Installed. No version info available.
> openai-agents: Installed. No version info available.
> openai<2.0.0,>=1.66.3: Installed. No version info available.
> opentelemetry-instrumentation-threading: Installed. No version info available.
> opentelemetry-semantic-conventions-ai: Installed. No version info available.
> orjson: 3.10.15
> packaging: 24.2
> packaging<25,>=23.2: Installed. No version info available.
> pydantic: 2.10.6
> pydantic-settings<3.0.0,>=2.4.0: Installed. No version info available.
> pydantic<3.0.0,>=2.5.2;: Installed. No version info available.
> pydantic<3.0.0,>=2.7.4: Installed. No version info available.
> pydantic<3.0.0,>=2.7.4;: Installed. No version info available.
> pymongo: 4.11.3
> pytest: Installed. No version info available.
> PyYAML>=5.3: Installed. No version info available.
> requests: 2.32.3
> requests-toolbelt: 1.0.0
> requests<3,>=2: Installed. No version info available.
> rich: 13.9.4
> simsimd: 6.2.1
> SQLAlchemy<3,>=1.4: Installed. No version info available.
> tenacity!=8.4.0,<10,>=8.1.0: Installed. No version info available.
> tenacity!=8.4.0,<10.0.0,>=8.1.0: Installed. No version info available.
> tiktoken<1,>=0.7: Installed. No version info available.
> typing-extensions>=4.7: Installed. No version info available.
> zstandard: 0.23.0

Labels: bug
State: closed